Disclosed is an electronic device having a thermal diffusion structure and including a housing comprising a first surface, a second surface facing the first surface, and a third surface vertical to the first surface and the second surface, a display exposed through at least part of the first surface, a battery arranged between the first surface and the second surface, a heating source arranged between the battery and the third surface in a direction vertical to the first surface and the second surface, and a first thermal diffusion member arranged vertically to the first surface and the second surface, the first thermal diffusion member including a first portion in thermal contact with at least part of the heating source and diffusing heat provided by the heating source to at least one second portion.