Longitudinal position of the headrest adjusting device

One kind longitudinal position adjusting means having a receiving head of an occupant load and the displacement of the displacement body longitudinal direction with respect to the headrest pillar; locking the displacement body front-rear direction at a plurality of positions and a releasable locking mechanism for locking the locking mechanism comprising: engaging portion integrally becomes bit and displacement thereof in the longitudinal direction; disposed on the rail engaging portion, and when a plurality of locking engagement with the engagement portion of the engagement portion, the engagement portion configured relative to said engaging portion is engaged from the lateral side of the card. Accordingly, the headrest can be suppressed thicker, lightweight and can be easily configured longitudinal position adjusting means.