An electronic device is provided with a device housing which includes an upper case and a lower case. A key input section is provided in the device housing and includes a key sheet disposed on an inner surface of the upper case. The key sheet has a plurality of key buttons exposed in an upper surface of the upper case and a plurality of pin holes provided at a plurality of positions excluding the key buttons. And, a plurality of fitting protrusions is provided on the inner surface of the upper case and inserted into and fitted in the pin holes of the key sheet.