An electronic device includes a housing including a front plate forming a first surface, a back plate forming a second surface, and a side member forming a side surface surrounding a space between the first and second surfaces; a sound output device disposed in the housing; an electrical component disposed in the housing and having a variable thickness; and a vibration damping member disposed on at least part of the electrical component or formed between the electrical component and the back plate. The vibration damping member is disposed in a variable space having a thickness varying depending on a thickness variation of the electrical component. The vibration damping member has a height varying in a thickness direction of the variable space to correspond to the thickness of the variable space and divides the variable space into a plurality of sub-spaces when the variable space has a specified thickness or more.