diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index e0fb5087af..6483eb541f 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -2200,6 +2200,9 @@ pages:
       _mod:
         arg1: "A"
         arg2: "B"
+      round: "少数を丸める"
+      _round:
+        arg1: "数"
       eq: "AとBが同じ"
       _eq:
         arg1: "A"
diff --git a/src/misc/aiscript/evaluator.ts b/src/misc/aiscript/evaluator.ts
index f6165afb64..857de13083 100644
--- a/src/misc/aiscript/evaluator.ts
+++ b/src/misc/aiscript/evaluator.ts
@@ -162,6 +162,7 @@ export class ASEvaluator {
 			multiply: (a: number, b: number) => a * b,
 			divide: (a: number, b: number) => a / b,
 			mod: (a: number, b: number) => a % b,
+			round: (a: number) => Math.round(a),
 			strLen: (a: string) => a.length,
 			strPick: (a: string, b: number) => a[b - 1],
 			strReplace: (a: string, b: string, c: string) => a.split(b).join(c),
diff --git a/src/misc/aiscript/index.ts b/src/misc/aiscript/index.ts
index 3a21e9b1cc..f2de1bb40d 100644
--- a/src/misc/aiscript/index.ts
+++ b/src/misc/aiscript/index.ts
@@ -24,6 +24,7 @@ import {
 	faExchangeAlt,
 	faRecycle,
 	faIndent,
+	faCalculator,
 } from '@fortawesome/free-solid-svg-icons';
 import { faFlag } from '@fortawesome/free-regular-svg-icons';
 
@@ -59,6 +60,7 @@ export const funcDefs: Record<string, { in: any[]; out: any; category: string; i
 	multiply:        { in: ['number', 'number'],           out: 'number',      category: 'operation',  icon: faTimes, },
 	divide:          { in: ['number', 'number'],           out: 'number',      category: 'operation',  icon: faDivide, },
 	mod:             { in: ['number', 'number'],           out: 'number',      category: 'operation',  icon: faDivide, },
+	round:           { in: ['number'],                     out: 'number',      category: 'operation',  icon: faCalculator, },
 	eq:              { in: [0, 0],                         out: 'boolean',     category: 'comparison', icon: faEquals, },
 	notEq:           { in: [0, 0],                         out: 'boolean',     category: 'comparison', icon: faNotEqual, },
 	gt:              { in: ['number', 'number'],           out: 'boolean',     category: 'comparison', icon: faGreaterThan, },