A magnetic disk drive apparatus includes a magnetic disk with a data region, a magnetic head located in a region of the magnetic disk other than the data region or outside of the magnetic disk before startup of the magnetic disk and loaded on the data region after the startup, and a current supply unit for providing, just after the startup, a dummy write current with a current value lower than a normal write current value to the magnetic head located in the region of the magnetic disk other than the data region or outside of the magnetic disk.