What is the difference between:




  • 2
    Are you asking this question knowing what the common set phrase 「(お)昼にする」 means? If so, the particle cannot be changed. See #3 here: jisho.org/search/%E6%98%BC
    – user4032
    Commented Nov 1, 2021 at 1:01

3 Answers 3


昼をしましょう would mean "Let's do noon", but not in the sense of "do" meaning "choose" as it can in English. And, "noon" is not something you can actively do or perform. Like, you can't use it as an answer to questions like "What do you like to do?" or "What should we do together?"

So this doesn't make sense (though, contrary to above, it is grammatical).


昼にする is a fixed phrase, but if you need to analyze it, I think you could see it as a special case of AをBにする as follows.


By the way, コーヒーにする could be seen like that, too.


昼をする makes little sense. 昼 in the sense of either “daytime” or “lunch” simply doesn’t work well as an object of the verb する.

  • How to say "to have lunch" in the neutral sense then? Is 昼する ok?
    – Starckman
    Commented Dec 29, 2022 at 10:21
  • 1
    @starckman - 昼ご飯を食べる
    – aguijonazo
    Commented Dec 29, 2022 at 21:10

...にする is a set expression indicating a choice one has/will make.


Well, how about lunch?

There was a time when saying things like let's do lunch or let's do dinner were viewed as horrible California-isms. It seems they've managed to have established themselves more broadly in English now.

But, in Japanese, saying


while this is technically grammatical, as pointed out in the other answer, it doesn't make much sense. (I was perhaps a bit careless in my use of the word, grammatical, previously.) 昼 here is being treated as the object of the verb する; you don't do afternoon in Japanese (even if you can make some kind of sense of that expression in English).

  • 1
    so, can お昼にしましょう translate to "lets decide to have lunch" ? @a-ellett Commented Oct 31, 2021 at 17:43
  • @yutrewq I would think that would depend on what you're talking about. Without context, it just sounds like making a plan for "something" and deciding on it being in the afternoon (whatever "it" may be).
    – A.Ellett
    Commented Oct 31, 2021 at 17:49
  • 1
    さて、昼にしましょう Well, how about afternoon? -- ん...? This「昼」 is short for 昼ごはん, right? eg 「そろそろ食事にしましょう。」「晩ご飯にしよう。」「メシにするか。」(But not 「朝にしましょう」「夜にしましょう」 for "Let's have/start breakfast/dinner")
    – chocolate
    Commented Nov 2, 2021 at 3:38

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .