～だけでなく
not only X but also
～だけでなく combines だけ (“only”) with でなく (“is not, and ...”), so it literally says “it is not only X”. The second half of the sentence then adds another fact, usually marked with も (“also”).
It is the everyday way to say “not only ... but also ...” in Japanese, and it attaches to nouns, adjectives, and plain-form verbs alike.
Adding a second fact beyond the first
Use ～だけでなく when stopping at the first fact would undersell the situation.
彼は頭がいいだけでなく、優しい。
“He's not only smart but also kind.”
- 彼（かれ）= he
- は = topic marker
- 頭がいい（あたまがいい）= smart (literally “head is good”)
- だけでなく = not only
- 優しい（やさしい）= kind
この店は安いだけでなく、料理もおいしい。
“This restaurant is not only cheap, the food is also delicious.”
- この = this
- 店（みせ）= shop, restaurant
- は = topic marker
- 安い（やすい）= cheap
- だけでなく = not only
- 料理（りょうり）= food, cooking
- も = also
- おいしい = delicious
Compare this with ～ばかりでなく: the meaning is identical, but ～だけでなく is the more conversational of the two, while ～ばかりでなく leans slightly formal or written.
How to form it
Noun / adjective / plain-form verb + だけでなく, with も in the second clause
- 安い（やすい）= cheap → 安いだけでなく = not only cheap
- 日本（にほん）= Japan → 日本だけでなく = not only Japan
- 読む（よむ）= to read → 読むだけでなく = not only reads
Key idea
～だけでなく adds another fact beyond the first one: not only X is true, but Y is true as well.
Built on the same stem
Updated .