To provide a headrest of a vehicular seat that can more control an occupant becoming a whiplash injury by reducing more a burden to a neck of the occupant on the occurrence of a rear end collision etc.

In a headrest 5 of a vehicular seat that includes: a pad part 5A that supports a head of an occupant; and a stay part 5B that supports the pad part 5A, the stay part 5B is curved to the backward when the load from the head to backward is applied, and is restored to a former shape when the load is lost. In the stay part 5B, there is provided a damper mechanism that delays restoring speed when restoring from the backward curved state that curves to the backward by the load to the backward to the former shape when the load is lost.