Does anyone know what this says? My dad got it from WW2?

All the characters appear on the box are traditional Chinese characters.
受: receive
信: singal
機: machine
線: wires/cables
輪: wheel
箱: box
四五九0 三號: serial no is 45903
Receive signal machine (mobile signal receiver) could a wire-controlled explosive device, or a short-distance communication device, etc. in WWII.
Wires/cables wheel box: a wheeled box that keep cables/wires neatly stored

You'd get better answers if you asked this on a Japanese web site.

Go to Google translate, translate your question and stick it on a Japanese forum (google can also translate foreign language web sites for you.)

Definitely Japanese, in Chinese it would not have been phrased that way.. 受信機 線輪箱 (The last word is a little faded out)
It's a case containing wire for a radio receiver.

Pick me for best answer if you find this useful. :P

Chinese writing, could be written by a Japanese person, intelligible to either.

Numerals in the left column are 四五九0三 which is 45903.

It'd be too much trouble for me to look up the rest of it. Anyone who can read Chinese can explain it.