A movable headrest provided on a seat back of a seat mounted in a vehicle and capable of changing a position from a normal position to an emergency position, the headrest including a headrest support supported by the seat back and having a guide section, a rotary support member pivotally supported by the headrest support and rotatable between a first position corresponding to the normal position and a second position corresponding to the emergency position, and a headrest body pivotally supported by the rotary support member and having a headrest body support which moves along the guide section, whereby as the rotary support member rotates relative to the headrest support, the position of the headrest body relative to the headrest support changes while the headrest body support moves along the guide section.