Upon recording, a clearance control unit performs preheating by an added control value (BR) of a base heater control value B and an adjustment heater control value R and switches that to value B when it reaches a target sector to perform write. Upon reproduction, preheating is performed by the value (BR) and the value (BR) is maintained when it reaches a target sector to perform read. A correction processing unit detects contact between the head and a medium surface while increasing the value R from a predetermined initial value Ro, and sets a new calculated base heater control value B, and value Ro as the adjustment heater control value R. Write assist adjustment in which the measured adjustment heater control value R is adjusted to a heater control value that improves characteristic deterioration immediately after recording is started wherein preheating is switched to write heating is performed.