This phrase means you must not do something. It shows that doing it is not allowed.
Verb [て-form] + は + いけませんPrimary
This phrase means you must not do something. It shows that doing it is not allowed.
図書館では走ってはいけません。
You must not run in the library.
当時は、子供はその森に入ってはいけませんでした。
In those days, children were not allowed to enter that forest.
ここでは写真を撮ってはいけませんから、カメラをしまってください。
Since you are not allowed to take photos here, please put your camera away.
運転する前にお酒を飲んではいけません。
You must not drink alcohol before driving.
この薬は空腹時に服用してはいけません。
You must not take this medicine on an empty stomach.
This phrase is like a boss telling you what to do. Only people with power use it. Like a teacher to a student. You would not use it to tell your boss what to do.
This rule is very strong. It is like saying 'You must not do this.' It is more formal than '〜てはだめ'. That phrase is often used by parents to children. '〜ちゃだめ' is for friends. This rule is for public signs or when someone important is speaking.
Use this when you want to say something is not allowed. It is very strong. You see it on signs or in rules. In talking, people use a slightly softer form.
Contrasts with(1)
More formal alternatives(1)
Track your mastery
Kumi's KMT system tracks your mastery across kanji, vocabulary, grammar, and reading. Create a free account to use it on 220,000+ concepts.