A foldable electronic device is provided, which includes a flexible display; a hinge assembly configured to fold and unfold a first area and a second area of the flexible display onto and away from each other; and a heat diffusion member. The hinge assembly includes a first hinge frame attached to a bottom face of the first area via a first adhesive member; a second hinge frame attached to a bottom face of the second area via a second adhesive member; a hinge pivotally connecting the first hinge frame and the second hinge frame to each other; and a hinge housing including a space, which accommodates the hinge, and connecting the first hinge frame and the second hinge frame to each other. At least a partial area of the heat diffusion member may be disposed between the flexible display and the hinge housing, in the space or at a position communicating with the space.