An electronic device including a cover having an open/close structure is provided. The electronic device includes a housing including an upper face and a recess formed through the upper face in order to accommodate an earphone device, a cover for covering the recess in a closed state and to allow access to the recess in an opened state, a conductive pin disposed in the recess and biased mechanically toward the cover in the closed state, a circuit electrically connected to the conductive pin, a plurality of magnets disposed in the cover, a mechanical hook structure coupled to a peripheral portion of the cover in the closed state, and a button, when pressed, for separating the hook structure from the peripheral portion while moving a magnet to a position where the magnet faces another magnet.