According to one embodiment, a disk device includes a housing including a bottom wall including a protrusion with a first surface, a recording medium arranged in the housing, a printed circuit board attached to the bottom wall, an electronic component mounted on the printed circuit board and including a second surface facing the first surface, and a radiation sheet including a third surface which is contact with the first surface, and a fourth surface which is in contact with the second surface. An area of the first surface is less than an area of the third surface of the radiation sheet, or an area of the second surface is less than an area of the fourth surface of the radiation sheet.