A magnetic disk drive having a small decrease in lubricant film thickness on the surface of the magnetic disk and a superior sliding reliability between the magnetic head and the magnetic disk surface. Perfluoropolyether is supplied as the lubricant onto the surface of the magnetic disk using heat and air flow by applying perfluoropolyether onto the surface of a suspension, or impregnating perfluoropolyether into a filter. The lubricant contains perfluoropolyether having a molecular weight sufficient to enable lubrication and smaller than 4000 by at least 40%.