MAGNETIC DISK DEVICE

According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head including a write head, a read head, a heater which adjusts a flying height of the read head and a detection portion which detects a flying height of the read head, and a controller which controls a power value supplied to the heater in accordance with the flying height, and, when a read error occurs, detects, with the detection portion, the flying height of the read head in an error occurrence region, determines an assist amount to bring the flying height in the error occurrence region to a pre-set reference flying height, and executes re-try read of the error occurrence region while inputting a power value corresponding to the assist amount to the heater.