According to one embodiment, in a disk device, a controller, when the rotation waiting time is present, increases an absolute value of a motor current in a fourth section in a second period in which a head is accelerated or decelerated, changes the absolute value of the motor current at a third average change rate in a fifth section after the fourth section in the second period, decreases the absolute value of the motor current at a fourth average change rate steeper than the third average change rate in a sixth section after the fifth section in the second period, and decreases the absolute value of the motor current at a fifth average change rate steeper than the fourth average change rate in a seventh section after the sixth section in the second period.