Japanese Language Stack Exchange is a question and answer site for students, teachers, and linguists wanting to discuss the finer points of the Japanese language. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I think this is a question I should have asked a long time ago.. What is the difference between 案外 and 意外? What does the correct situation look like when using either?

Example with 案外:


Example with 意外:


The English translation definitely didn't help me with this one, as both are "unexpectedly". Is there a certain degree that is associated with each?

share|improve this question
We say 「意外な出来事」「それは意外だ。」but not 「案外な出来事」「それは案外だ」... But I don't see much difference between 「意外と/意外に簡単だった」and「案外簡単だった」. 意外と/意外に might sound a bit more casual than 案外... and I think 意外 has a nuance of a surprise, and 意外 sounds more subjective while 案外 sounds more objective. – user1016 Jul 24 '12 at 16:57
@Chocolate As for that contrast, my answer gives a clue. 案外 requires some quantity that turns out to be inferior, whereas 意外 is used generally. So 案外 can be replaced with 意外, but the opposite is not necessarily true. 意外な出来事, それは意外だ do not involve a quantity, and that is why it cannot be replaced with 案外. 簡単 involves quantity, and hence can be used with 案外. – user458 Jul 24 '12 at 17:17
up vote 1 down vote accepted
  • 意外 "unexpectedly"
  • 案外 "after all", "unexpectedly in such a way that something is inferior than it was originally thought"

Implication: Life is thought to be long.

In your examples, they can be switched with some adjustment in the form.

Implication: People thought it would be more difficult than it turned out to be.

share|improve this answer

I've always thought of them in terms of their kanji make-up.

  • : can mean "plan/expectation"
  • : can mean "idea/mind/thought" (with the thought process maybe implying some subjectivity)

From there:

  • 案外:

    • "not according to plans/expectations"
    • "[contrary to/against] expectations"
    • often, but not always "disappointing(ly)"
  • 意外(に・と):

    • "[against/not] what was [thought/expected]"/"(I/you) wouldn't have thought"
    • "surprising(ly)"

Daijisen has some usage notes differentiating the two in the definition for 案外. I think it basically says:

  • 案外 is used when expectations/situations turn out different:

    I had [expectations/hopes], but it was a disappointingly boring movie.

    I was worrying, but contrary to expectations, the job was easy.

  • 意外な/意外に are used when the reality is different to what was thought, or with things that can't be expected:

    Time passed surprisingly quickly.

share|improve this answer

意外」 is used when what you're describing is unexpected.

案外」 is used when what you're describing is contrary to what you expected and is most frequently used with adjectives.

「案外安い」 OK
「案外簡単」 OK

However, I don't believe that you can say 「案外に」 the way that you would say 「意外に」

「案外に安い」 NG ⇒ 「意外に安い」 OK
「案外に簡単」 NG ⇒ 「意外に簡単」 OK
share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.