According to an embodiment, there is provided a disk device including a disk, a head, a preamplifier and a controller. The head writes information to the disk according to a write current. The preamplifier causes the write current to flow through the head. The controller is capable of causing the preamplifier to perform current zero control for maintaining an amplitude of the write current at zero, and is capable of changing a time for maintaining the amplitude of the write current at zero according to a pattern of write data.