PURPOSE: To restrain a lubricating layer on a disc medium from vanishing and improve CSS characteristics by supplementing a lubricant from outside the disc medium selectively in space and instantaneously in time when a lubricating film of the disc medium is broken.

CONSTITUTION: A magnetic disc medium 12 is set in a case 10 of a magnetic disc apparatus. A supplementing body 14 of a polarity (bipolar moment) lubricant impregnated with ethylene glycol or diethylene glycol is provided not on the magnetic disc medium 12, but on a fixed part. Molecules of the lubricant evaporating from the supplementing body 14 are deposited by chemical adsorption selectively on a part where a lubricating film on the disc is broken (active part), so that the lubricating film is quickly mended.