To constitute a tilting device for head reset of a smaller number of parts, easily set at a tilted location by the urging force of an urging member such as a spring, and also, surely keep a head rest body at a standing location and a tilted location.

A fixed plate 1 on which a lock pin 30 is provided, is fixed to a stay, and at the same time, a tilting plate 2 having a cam hole 5 to guide the lock pin 30, is rotatably held by a stay 200, and a coil spring 4 which respectively urges the lock pin 30 and the tilting plate 2, is arranged. When the tilting plate 2 is slightly tilted forward from a standing location, the engagement of the lock pin 30 at the standing location is released, and the tilting plate 2 automatically tilts backward by the coil spring 4 without stopping at the standing location, and is held at the tilted location, and when the tilting plate 2 is lifted forward from the tilted location, the lock pin 30 is engaged again, and the tilting plate 2 is held at the standing location.