diff --git a/docs/rules/numeric-separators-style.md b/docs/rules/numeric-separators-style.md
index 843f75d8d9..a15986233e 100644
--- a/docs/rules/numeric-separators-style.md
+++ b/docs/rules/numeric-separators-style.md
@@ -33,6 +33,23 @@ If you want a custom group size for a specific number type, you can specify it h
 
 There are four number types; [`hexadecimal`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Lexical_grammar#Hexadecimal), [`binary`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Lexical_grammar#Binary), [`octal`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Lexical_grammar#Octal) and [`number`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type). Each of them can be associated with an object containing the following options:
 
+**`onlyIfContainsSeparator`**
+
+Type: `boolean`\
+Default: `false`
+
+Check if the group sizes are valid **only** if there are groups separated with an `_`.
+You can set it at top-level, or override for each specific number type.
+
+Example:
+
+```js
+// eslint unicorn/numeric-separators-style: ["error", {"onlyIfContainsSeparator": true, "binary": {"onlyIfContainsSeparator": false}]
+const number = 100000; // Pass, this number does not contains separators
+const binary = 0b101010001; // Fail, `binary` type don't require separators
+const hexadecimal = 0xD_EED_BEE_F; // Fail, it contain separators and it's incorrectly grouped
+```
+
 **`minimumDigits`**
 
 Type: `number`
@@ -95,6 +112,7 @@ const foo = 0o12_7777;
 
 ```js
 {
+	onlyIfContainsSeparator: false,
 	hexadecimal: {
 		minimumDigits: 0,
 		groupLength: 2
diff --git a/rules/numeric-separators-style.js b/rules/numeric-separators-style.js
index 5411820476..5810e99ae5 100644
--- a/rules/numeric-separators-style.js
+++ b/rules/numeric-separators-style.js
@@ -1,5 +1,5 @@
 'use strict';
-const {defaultsDeep, fromPairs} = require('lodash');
+const {fromPairs} = require('lodash');
 const getDocumentationUrl = require('./utils/get-documentation-url');
 
 const MESSAGE_ID = 'numeric-separators-style';
@@ -47,12 +47,7 @@ function formatNumber(value, options) {
 	return formatted;
 }
 
-function format(value, options) {
-	const {
-		prefix = '',
-		data
-	} = value.match(/^(?<prefix>0[box])?(?<data>.*)$/i).groups;
-
+function format(value, {prefix, data}, options) {
 	const formatOption = options[prefix.toLowerCase()];
 
 	if (prefix) {
@@ -70,18 +65,44 @@ function format(value, options) {
 }
 
 const defaultOptions = {
-	hexadecimal: {minimumDigits: 0, groupLength: 2},
 	binary: {minimumDigits: 0, groupLength: 4},
 	octal: {minimumDigits: 0, groupLength: 4},
+	hexadecimal: {minimumDigits: 0, groupLength: 2},
 	number: {minimumDigits: 5, groupLength: 3}
 };
 const create = context => {
-	const rawOptions = defaultsDeep({}, context.options[0], defaultOptions);
+	const {
+		onlyIfContainsSeparator,
+		binary,
+		octal,
+		hexadecimal,
+		number
+	} = {
+		onlyIfContainsSeparator: false,
+		...context.options[0]
+	};
+
 	const options = {
-		'0b': rawOptions.binary,
-		'0o': rawOptions.octal,
-		'0x': rawOptions.hexadecimal,
-		'': rawOptions.number
+		'0b': {
+			onlyIfContainsSeparator,
+			...defaultOptions.binary,
+			...binary
+		},
+		'0o': {
+			onlyIfContainsSeparator,
+			...defaultOptions.octal,
+			...octal
+		},
+		'0x': {
+			onlyIfContainsSeparator,
+			...defaultOptions.hexadecimal,
+			...hexadecimal
+		},
+		'': {
+			onlyIfContainsSeparator,
+			...defaultOptions.number,
+			...number
+		}
 	};
 
 	return {
@@ -101,7 +122,15 @@ const create = context => {
 				return;
 			}
 
-			const formatted = format(number.replace(/_/g, ''), options) + suffix;
+			const strippedNumber = number.replace(/_/g, '');
+			const {prefix = '', data} = strippedNumber.match(/^(?<prefix>0[box])?(?<data>.*)$/i).groups;
+
+			const {onlyIfContainsSeparator} = options[prefix.toLowerCase()];
+			if (onlyIfContainsSeparator && !raw.includes('_')) {
+				return;
+			}
+
+			const formatted = format(strippedNumber, {prefix, data}, options) + suffix;
 
 			if (raw !== formatted) {
 				context.report({
@@ -117,6 +146,9 @@ const create = context => {
 const formatOptionsSchema = ({minimumDigits, groupLength}) => ({
 	type: 'object',
 	properties: {
+		onlyIfContainsSeparator: {
+			type: 'boolean'
+		},
 		minimumDigits: {
 			type: 'integer',
 			minimum: 0,
@@ -133,9 +165,15 @@ const formatOptionsSchema = ({minimumDigits, groupLength}) => ({
 
 const schema = [{
 	type: 'object',
-	properties: fromPairs(
-		Object.entries(defaultOptions).map(([type, options]) => [type, formatOptionsSchema(options)])
-	),
+	properties: {
+		...fromPairs(
+			Object.entries(defaultOptions).map(([type, options]) => [type, formatOptionsSchema(options)])
+		),
+		onlyIfContainsSeparator: {
+			type: 'boolean',
+			default: false
+		}
+	},
 	additionalProperties: false
 }];
 
diff --git a/test/numeric-separators-style.js b/test/numeric-separators-style.js
index 784377401d..62d2dcdab0 100644
--- a/test/numeric-separators-style.js
+++ b/test/numeric-separators-style.js
@@ -1,3 +1,4 @@
+import {outdent} from 'outdent';
 import {test} from './utils/test.js';
 
 const error = {
@@ -104,6 +105,123 @@ test({
 		{
 			code: 'const foo = 0b111',
 			options: [{number: {minimumDigits: 3, groupLength: 1}}]
+		},
+		{
+			code: outdent`
+				const binary = 0b10101010;
+				const octal = 0o76543210;
+				const hexadecimal = 0xfedcba97;
+				const number = 12345678.12345678e12345678;
+			`,
+			options: [{
+				onlyIfContainsSeparator: true
+			}]
+		},
+		{
+			code: outdent`
+				const binary = 0b1010_1010;
+				const octal = 0o76543210;
+				const hexadecimal = 0xfedcba97;
+				const number = 12345678.12345678e12345678;
+			`,
+			options: [{
+				onlyIfContainsSeparator: true,
+				binary: {
+					onlyIfContainsSeparator: false
+				}
+			}]
+		},
+		{
+			code: outdent`
+				const binary = 0b10_10_10_10;
+				const octal = 0o76543210;
+				const hexadecimal = 0xfedcba97;
+				const number = 12345678.12345678e12345678;
+			`,
+			options: [{
+				onlyIfContainsSeparator: true,
+				binary: {
+					onlyIfContainsSeparator: false,
+					groupLength: 2
+				}
+			}]
+		},
+		{
+			code: outdent`
+				const binary = 0b10101010;
+				const octal = 0o7654_3210;
+				const hexadecimal = 0xfe_dc_ba_97;
+				const number = 12_345_678.123_456_78e12_345_678;
+			`,
+			options: [{
+				binary: {
+					onlyIfContainsSeparator: true
+				}
+			}]
+		},
+		{
+			code: 'const foo = 12345',
+			options: [{number: {onlyIfContainsSeparator: true}}]
+		},
+		{
+			code: 'const foo = 12345678',
+			options: [{number: {onlyIfContainsSeparator: true}}]
+		},
+		{
+			code: 'const foo = 12_345',
+			options: [{number: {onlyIfContainsSeparator: true}}]
+		},
+		{
+			code: 'const foo = 1789.123_432_42',
+			options: [{number: {onlyIfContainsSeparator: true}}]
+		},
+		{
+			code: 'const foo = -100_000e+100_000',
+			options: [{number: {onlyIfContainsSeparator: true}}]
+		},
+		{
+			code: 'const foo = -100000e+100000',
+			options: [{number: {onlyIfContainsSeparator: true}}]
+		},
+		{
+			code: 'const foo = -282_932 - (1938 / 10_000) * .1 + 18.100_000_2',
+			options: [{number: {onlyIfContainsSeparator: true}}]
+		},
+		{
+			code: 'const foo = 0xA_B_C_D_E',
+			options: [{hexadecimal: {onlyIfContainsSeparator: true, groupLength: 1}}]
+		},
+		{
+			code: 'const foo = 0o7777',
+			options: [{octal: {onlyIfContainsSeparator: true, minimumDigits: 4}}]
+		},
+		{
+			code: 'const foo = 0xABCDEF012',
+			options: [{hexadecimal: {onlyIfContainsSeparator: true}}]
+		},
+		{
+			code: 'const foo = 0o777777',
+			options: [{octal: {onlyIfContainsSeparator: true, minimumDigits: 3}}]
+		},
+		{
+			code: 'const foo = 0o777777',
+			options: [{octal: {onlyIfContainsSeparator: true, minimumDigits: 3, groupLength: 2}}]
+		},
+		{
+			code: 'const foo = 0o777_777',
+			options: [{octal: {onlyIfContainsSeparator: true, minimumDigits: 2, groupLength: 3}}]
+		},
+		{
+			code: 'const foo = 0b01010101',
+			options: [{onlyIfContainsSeparator: true, binary: {onlyIfContainsSeparator: true}}]
+		},
+		{
+			code: 'const foo = 0b0101_0101',
+			options: [{onlyIfContainsSeparator: false, binary: {onlyIfContainsSeparator: true}}]
+		},
+		{
+			code: 'const foo = 0b0101_0101',
+			options: [{onlyIfContainsSeparator: false, binary: {onlyIfContainsSeparator: false}}]
 		}
 	],
 	invalid: [
@@ -327,6 +445,93 @@ test({
 			options: [{number: {minimumDigits: 3, groupLength: 2}}],
 			errors: [error],
 			output: 'const foo = 0b111'
+		},
+		{
+			code: 'const foo = -100000e+100000',
+			options: [{number: {onlyIfContainsSeparator: false}}],
+			errors: [error],
+			output: 'const foo = -100_000e+100_000'
+		},
+		{
+			code: outdent`
+				const binary = 0b10_101010;
+				const octal = 0o76_543210;
+				const hexadecimal = 0xfe_dcba97;
+				const number = 12_345678.12345678e12345678;
+			`,
+			output: outdent`
+				const binary = 0b1010_1010;
+				const octal = 0o7654_3210;
+				const hexadecimal = 0xfe_dc_ba_97;
+				const number = 12_345_678.123_456_78e12_345_678;
+			`,
+			options: [{
+				onlyIfContainsSeparator: true
+			}],
+			errors: 4
+		},
+		{
+			code: outdent`
+				const binary = 0b10101010;
+				const octal = 0o76_543210;
+				const hexadecimal = 0xfe_dcba97;
+				const number = 12_345678.12345678e12345678;
+			`,
+			output: outdent`
+				const binary = 0b1010_1010;
+				const octal = 0o7654_3210;
+				const hexadecimal = 0xfe_dc_ba_97;
+				const number = 12_345_678.123_456_78e12_345_678;
+			`,
+			options: [{
+				onlyIfContainsSeparator: true,
+				binary: {
+					onlyIfContainsSeparator: false
+				}
+			}],
+			errors: 4
+		},
+		{
+			code: outdent`
+				const binary = 0b10101010;
+				const octal = 0o76_543210;
+				const hexadecimal = 0xfe_dcba97;
+				const number = 12_345678.12345678e12345678;
+			`,
+			output: outdent`
+				const binary = 0b10_10_10_10;
+				const octal = 0o7654_3210;
+				const hexadecimal = 0xfe_dc_ba_97;
+				const number = 12_345_678.123_456_78e12_345_678;
+			`,
+			options: [{
+				onlyIfContainsSeparator: true,
+				binary: {
+					onlyIfContainsSeparator: false,
+					groupLength: 2
+				}
+			}],
+			errors: 4
+		},
+		{
+			code: outdent`
+				const binary = 0b10_101010;
+				const octal = 0o76543210;
+				const hexadecimal = 0xfedcba97;
+				const number = 12345678.12345678e12345678;
+			`,
+			output: outdent`
+				const binary = 0b1010_1010;
+				const octal = 0o7654_3210;
+				const hexadecimal = 0xfe_dc_ba_97;
+				const number = 12_345_678.123_456_78e12_345_678;
+			`,
+			options: [{
+				binary: {
+					onlyIfContainsSeparator: true
+				}
+			}],
+			errors: 4
 		}
 	]
 });