Disclosed are various embodiments of an electronic device including a key module for hermetically sealing an inside of the device. According to one embodiment, a portable device includes: a front cover; a rear cover; and a bezel that surrounds at least a portion of a space formed between the front and rear covers, and includes a first portion and an opening. Disposed within the space is a display including a screen exposed through the front cover; a plate including a support surface with multiple protrusions and an accommodation hole that provides a pathway leading to the opening; a key; and a first member including a via hole through which a portion of the key passes. When the key is inserted into the pathway and moved in a first direction, the inside space of the electronic device is hermetically sealed from the outside.