Disk device

One embodiment provides a disk device capable of appropriately performing a write operation. According to one embodiment, there is provided a disk device including a first disk, a first head, a first actuator, and a controller. The first actuator moves the first head relative to the first surface of the first disk. The controller performs positioning control on the first head via the first actuator, and controls a writing operation of the first head on the first disk. The controller acquires information relating to the state of the vibration source. The controller changes the value of a coefficient for estimating the predicted position of the first head on the basis of information relating to the state of the vibration source. The controller estimates the predicted position of the first head using the value of the changed coefficient. The controller performs a write operation of the first head when the estimated predicted position is equal to or less than a threshold value, and prohibits the write operation o