文法Grammar Point
ni chigai nai · JLPT N3
〜に違いない means “must be / no doubt”. It is a JLPT N3 pattern: below are its construction, the nuances that trip learners up, and the sentences where real Japanese writers use it.
A free one-page study card for 〜に違いない (must be / no doubt), JLPT N3: what it means, how it attaches, 3 example sentences with furigana, and the nuances that trip learners up. Read it right here, or take the PDF or PNG with you. We never ask for an email for this card.
誰もいない。もう帰ったに違いない is “Nobody’s here. They must have gone home.” Attach it to plain forms; nouns and な-adjectives attach directly, with no だ. It sits at the confident end of the certainty scale, well past かもしれない and でしょう: you have not verified the fact, but you are in no doubt about it.
構文Construction
Verb / い-adjective (plain) + に違いない
電気がついている。まだ起きているに違いない。 — The light’s on. They must still be up.
Noun / な-adjective (no だ) + に違いない
あの人は先生に違いない。 — That person must be a teacher.
Polite: 〜に違いありません
彼女はこの町の出身に違いありません。 — She must be from this town.
Concluding about the past: 〜たに違いない
道が濡れている。雨が降ったに違いない。 — The road is wet. It must have rained.
例文In a sentence
電気がついている。まだ起きているに違いない。
道が濡れている。雨が降ったに違いない。
彼女はこの町の出身に違いありません。
注意点Nuances
練習Your Turn
Each one is quoted from a published Japanese text in this library and links to the story it came from. Some use older spellings, or break off where the sentence carried on. They are transcribed exactly as their authors wrote them.
どうしてもこれは烏啼の部下から本部又は碇健二へ送った情報に違いない。
— from The Role of the Cipher (N1)
無暗と騒ぐので四方で迷惑したに違いない。
— from Ski Diary at Goshiki Hot Springs (N1)
お父様はきっと薬屋さんに違いないわ。
— from The Big Umbrella (N3)
私の顔色は確かに、灰のようになっていたのに相違ございません。
— from Two Letters (N1)
3 sentences taken from real Japanese texts, with the grammar removed. Pick what belongs in the gap.
Question 1 of 3
お父様はきっと薬屋さんblankわ。
Answer: に違いない — from The Big Umbrella (N3)
どうしてもこれは烏啼の部下から本部又は碇健二へ送った情報blank。
Answer: に違いない — from The Role of the Cipher (N1)
無暗と騒ぐので四方で迷惑したblank。
Answer: に違いない — from Ski Diary at Goshiki Hot Springs (N1)
Read the texts these came from
Every sentence above came from a free text you can read here in full, with the rest of the story around it.
Appears in 6 of 367 texts in our library.
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解説Background
〜に違いない sits at JLPT N3 in the 302-point taxonomy every text in this library is tagged against. Each text is read for the patterns it contains, which is what lets this page list every text that uses 〜に違いない and pull its example sentences out of them.
The example sentences were not written to demonstrate the rule. They are quoted from published Japanese texts in this library (The Role of the Cipher and Ski Diary at Goshiki Hot Springs among them), and each one links back to the story it came from, so you can read the sentence where it actually happened.
質問Questions
Very. It means you have no doubt, even though you have not checked. On the scale of Japanese guesses it sits above かもしれない (might), でしょう (probably) and はずだ (should be) — only a plain statement of fact is stronger.
No. Nouns and な-adjectives attach directly: 学生に違いない, 本当に違いない. Verbs and い-adjectives use their plain form as usual: 行くに違いない, 高いに違いない.
はずだ reasons from a rule or an expectation — 三時の便だから、もう着いているはずだ. に違いない reasons from evidence and conviction — 靴がある。まだ家にいるに違いない. はずだ can be wrong without surprise; に違いない sounds shaken if it is.
Yes. A free one-page 〜に違いない (must be / no doubt) study card sits at the top of this page, as both a PDF and a PNG. It carries the JLPT N3 meaning, how the pattern attaches, 3 example sentences with furigana, and the nuances learners get wrong. You do not need an account or an email address to download it.
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