To reduce shock generated when a nut collides with a stopper such as a bush.

A damper device has a screw mechanism 30 converting linear movement into rotational movement by a ball screw. In the male screw part 32a of a screw shaft 32, the screw lead L1 formed in a neutral area A1 is formed to have the same lead as a female screw part 34a, and the screw lead L2 formed in a braking area A2 other than the neutral area is formed smaller than the screw lead L1 formed in the neutral area A1 (L2L1). Thereby, when the nut 34 is displaced in the braking area A2, since frictional resistance between the nut 34 and the screw shaft 32 is increased in comparison with a case where the nut is displaced in the neutral area A1, the nut 34 is prevented from being largely displaced when the nut is displaced from the neutral area A1 of the male screw part 32a to the braking area A2 thereof. Therefore, the shock generated when the nut 34 collides with the bush 52 can be reduced.