The purpose of the present invention is to provide a headrest to be infallibly locked when returned from a forward tilted position to a using position, without requiring high part accuracy and assembly accuracy. A vehicle seat headrest (4) according to the present invention, having: a stay (402) held on the seat back side; and a headrest main body (4A) supported forward rotatably from a using position with respect to the stay (402), includes: a locking mechanism (500) that fixes a rotation position of the headrest main body (4A) with respect to the stay (402) in the using position; and a stopper mechanism (600) that is not engaged with a regulation part in the using position, but is engaged with the regulation part when the headrest main body (4A) is tilted backward from the using position, to regulate backward tilting of the headrest main body (4A).