A magnetic recording/reproducing apparatus and method, the apparatus including a drive mechanism for driving a flexible magnetic disk loaded thereon to rotate, the magnetic disk being comprised of a transparent and flexible base film formed with first and second magnetic layers on both sides thereof, each of the magnetic layers having a film thickness of no greater than 1 .mu.m, surface of the first magnetic layer being flat, the outer surface of the second magnetic layer on the side away from the first magnetic layer, being provided with recesses for tracking servocontrol extending in the direction of rotation of the magnetic disk; a light emitting element for tracking servocontrol arranged on the side of the magnetic disk facing the first magnetic layer; and a light receiving element for receiving a light beam for tracking servocontrol, the light beam having passed through at least the first magnetic layer, the base film and the second magnetic layer after being emitted from the light emitting element, whereby using the light that has passed through the magnetic disk, proper tracking servocontrol is realized with high reliability, while improving an overwrite characteristic and undergoing less noise.