In accordance with another aspect of the present disclosure, an electronic device includes a display; an upper housing surrounding a periphery of the display and forming a front of the electronic device; a lower housing coupled to the upper housing and forming a rear of the electronic device; a speaker; a bracket, on which at least a portion of the speaker is seated and having at least a portion of a speaker sound hole, from which an audio signal generated by the speaker is output; a speaker hole formed on one side of the lower housing and aligned with the speaker sound hole; and a speaker waterproof member configured to seal an aperture between at least part of the lower housing having the speaker hole and at least part of the bracket having the speaker hole. The speaker waterproof member includes an outer sheath composed of a first material; and an inner core composed of a second material more rigid than the first material and disposed substantially in the outer sheath such that each of an upper surface and a lower surface of the inner core facing the front and the rear of the electronic device, respectively, does not protrude out of a periphery of the outer sheath