According to one embodiment, a disk device includes a base having a bottom wall, a motor provided on the base, a disk rotatably supported on the motor, a head, and a head actuator which supports the head for movement with respect to the recording medium. The bottom wall of the base includes a recess opposing a movement region for the head actuator and a first step portion and a second step portion which individually extend from the vicinities of the motor to the vicinities of an outer peripheral edge of the recording medium and define the recess. At least a part of the first step portion is located on the opposite side of the head actuator with respect to a line which connects an outer end portion of the first step portion and a center of rotation of the recording medium.