An electronic device including a front cover, a back cover, and a sidewall configured to surround at least a part of an internal space formed between the front and back covers. Disposed in the space is a rear case including a first conductive connecting member formed therein; a first space formed between the back cover and the rear case; and a second space formed between the front cover and the rear case, the second space configured to be hermetically sealed from the first space. An electrical connecting member includes a first part disposed in the first space, a second part that extends to a surface of a non-conductive structure, and a third part electrically contacting the first conductive connecting member. A printed circuit board disposed within the second space is electrically connected with the first conductive connecting member. The sidewall may comprise an opening configured to receive a side key.