According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head including a write head which writes data to the magnetic disk, a read head which reads data from the magnetic disk, a first heater which adjusts a flying height of the write head, a second heater which adjusts a flying height of the read head and a controller which controls powers supplied to the first heater and the second heat, and controls a power value of the power supplied to the first heater according to a ratio between an electric resistance value of the first heater and an electric resistance value of the second heater.