A method for discriminating the operation type of a disk device uses an optical head carrying an objective lens. The gravity doesn't affect the control force of the optical head in the horizontal operation type, reduces the control force in a vertical operation type, and increases the control force in inverse operation type. Control forces based on various operation types forms different motion features of the optical head to discriminate the operation type. Damping characteristic parameters of each operation type of the optical head are previously determined by test first. The Control force is transported to the optical head, and the timer is reset. The displacement of the optical head is continuously detected till reaching a predetermined situation. The time of timer is read to compare with the threshold of each operation type for distinguishing the operation type.