A magnetic disk apparatus includes a magnetic recording medium that records information, a magnetic head slider flying over a surface of the magnetic recording medium to read or write information from or to the magnetic recording medium, a rear rail having a rear ABS and a rear stepped bearing surface on an air outflow side from which air flows out from the magnetic head slider, the rear stepped bearing surface being deeper than the rear ABS, and at least one closed vibration attenuation groove that is formed on the rear ABS of the rear rail with a depth greater than the rear ABS and has the rear stepped bearing surface on an air inflow side.