A compact headrest having a simplified and more compact mechanism is provided. The headrest includes a first and a second headrest pillars, and a stationary unit disposed therebetween. The stationary unit is movable in a vertical direction along the pillars. The headrest further includes a movable unit movable forward away from the stationary unit and rearward toward the stationary unit through a moving mechanism. The headrest further includes a front-rear locking mechanism having a lock receiver and a locking component engaging therewith. The front-rear locking mechanism locks and unlocks the movable unit moving in a front-rear direction to the stationary unit. The headrest further includes a vertical locking mechanism locking and unlocking the stationary unit stepwise in a vertical direction along the pillars. The headrest further includes an operation unit for simultaneously operating the front-rear locking mechanism and the vertical locking mechanism in a substantially identical direction.