Vehicle seat

A vehicle seat comprises a back frame (10) adapted to support a headrest (4), an elastic member (20) interconnecting a pair of side frames (12) of the back frame (10), a movable member (30) provided on the elastic member (20), and a restriction member (40) provided on the back frame (10) and engageable with the movable member (30). The movable member (30) and the restriction member (40) are adapted, when a rearward load applied to the elastic member (20) is less than a predetermined given value, to be placed in a first mode where the restriction member (40) and the movable member (30) are engaged with each other, and, when the load applied to the elastic member (20) becomes equal to or greater than the given value, to achieve a transition to a second mode where the engagement between the restriction member (40) and the movable member (30) is released, whereby, in the first mode, a rearward movement of the movable member (30) is restricted by the restriction member (40), so that a rearward bending amount of the elastic member (20) is limited, and, in the second mode, the rearward movement of the movable member (30) is permitted, so that the limitation on the bending amount of the elastic member (20) is released. The vehicle seat can adequately protect an occupant's neck region during a rear collision, with a simple structure.