According to the tobira textbook, ~だけでなく、~も~, means "not only ~, but also ~". One example they give is, 日本語はひらがなだけでなく、カタカナや漢字も覚えなくてはいけません。

For the last two examples, the grammar phrase being taught changes to ~だけじゃなくて、~も~. The examples are

  • このアパートは駅から近くて便利なだけじゃなくて、家賃も安いから、借りることにした。
  • その映画は面白いだけじゃなくて、音楽もいいよ。

Do だけでなく and だけじゃなく both have the same meaning here? I'm assuming they are the same or similar but I'm not sure. Is one a less formal version or the other? Are they identical?

Also, in my second example, why is 便利 followed by なだけ instead of just だけ? Is だけ perhaps a noun that 便利 is modifying?

3 Answers 3


The difference between でない and ではない is directly connected to the semantic impression the topic particle は would give in normal circumstances.

ではない appears to be generally preferred in distinct, independent predicative phrases, or when you are about to say "Something 'is' something, and so that...":

  • このアパートは駅から近くて便利なだけじゃなくて...

    "This apartment is not only convenient being near a station..."

  • その映画は面白いだけじゃなくて...

    "The movie is not only interesting..."

  • 人間たちが定命の者ではなかったら、間違いなく神にもっとも近い種族だったでしょう...

    "If human beings are not who lay down fate..."

Whereas でない can be seen employed in other environments including but not limited to:

  1. objects dependent on a verb phrase:


    "For Japanese you have to learn not only hiragana..."

  2. direct attributives which modify nouns:



    This type is rather straightforward.

  3. When directly preceding, especially having an immediate causal connection to, the main event/verb of the sentence:


    "Good that it wasn't mom...". In Japanese grammar context this use is closely related to the one above since adjectival/adverbial constructions are viewed as parallel, but such adverbial ones often lack a literal English parsing. In this case, *ママではなくてよかった would have meant something along the lines of "It wasn't mom, but (I was? That thing who wasn't mom was?) good" which doesn't make any sense since は would have elevated that part of the phrase to an independent level parallel to the main event よかった. To use は in this context, you have to add extra conjunctions and say for example ママではなかったからよかった.


    Similar to above. ヒールでなくダメ can also be correct, with the former putting more emphasis on a general case "if" and the latter more of a specific instance such as when a woman is stopped right before the entrance of a high-heel only venue.

    and one final example:


    which is almost exactly the same as the one above.

  4. isolated phrases where the integrity of a full sentence is not as emphasized; frequently in titles:



  • Wow, nice first contribution -- welcome! I know you're comparing でない and ではない here, but confusingly じゃない's distribution is different from both of them. It seems to work almost anywhere, like 〜じゃなくてよかった, 〜じゃないとダメ and such are fine despite ではない not working. Oct 19, 2015 at 21:39
  • だけじゃなく is an informal/casual form of だけでなく.
  • It's not "便利 + なだけ", but "便利な (na-adjective) + だけ".

I'll add an answer to your second question, to clarify Doncot's answer which feels rather partial.

じゃない is indeed a casual form of でない

When used to modify a whole sentence, だけ attaches to the rentaikei of the previous word. That's a fancy way for saying that if a sentence has だ at the end, it should be replaced with な:

  • verbs: このボタンを押すだけでいいよ。 (no change)
  • i-adjectives: 話し相手がほしいだけだ。 (no change)
  • nouns and 'na-adjectives': 必要なだけのお金を持ってきて。

The word also attaches to な-adjectives with the な intact: 好きなだけ

  • (I'm a bit unsure about this answer, so please take it with a grain of salt.)
    – oals
    Oct 17, 2015 at 9:43
  • 1
    「じゃない」 is not a casual form of 「でない」; It is of 「ではない」.
    – user4032
    Oct 17, 2015 at 10:49
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    I was under the impression that both でない and ではない map to じゃない
    – oals
    Oct 17, 2015 at 10:51
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    Etymologically it's certainly contracted from ではない and not でない, but I don't think it's as simple as that anymore. Martin discusses this on page 373 of his Reference Grammar of Japanese (1975, forty years ago), where he points out that some speakers use じゃない for both でない and ではない. You might also be interested in this paper which compares use of でない・ではない・じゃない in BCCWJ by birth year of author: ninjal.ac.jp/event/specialists/project-meeting/files/… The chart on page 280 makes it look like じゃない is taking over for both でない and ではない.
    – user1478
    Oct 19, 2015 at 20:31

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