An electronic device includes a display, an upper housing surrounding at least a portion of a periphery of the display, a lower housing coupled to the upper housing, and a window waterproof member disposed between at least a portion of a periphery of the display and the upper housing to seal an aperture between the upper housing and the display. The window waterproof member includes an inner core having a specific strength, and an outer sheath having a specific elasticity, and an outer peripheral surface of which contacts at least part of the upper housing and an inner peripheral surface of which contacts at least part of the display while the outer sheath surrounding at least a portion of the inner core.