Abstract: An improved loading mechanism for a magnetic disk device comprises a rack provided on a movable plate, and a rotary oil damper provided on a fixed or stationary member and having a gear wheel provided thereon, whereby the rack is engaged with the gear wheel so as to control a speed of slipping movement of the movable plate causes by a force of a return spring. Accordingly, a force of a second magnetic head to collide with a first magnetic head is reduced, and hence damage to a flexible disk or break of a magnetic head can be minimized while the reliability of the system is improved.