A vehicle headrest apparatus has a headrest unit mounted to an upper end of a seatback. The headrest unit has a headrest members with a head restraining member configured to be tensioned to restrain a passenger's head upon a rear-end collision. The headrest unit quickly and reliably restrains a seated passenger's head during a rear-end collision without utilizing the inertia force of the passenger's body by detecting the rear-end collision and pushing the headrest unit only outward in the forward direction of the vehicle. The headrest unit also has a swing/pushup device that to pushes the headrest members upwardly and forwardly. An auxiliary swing force adding device applies an auxiliary spring force in the deployment direction of the headrest members to increase the deployment speed of the headrest members and shorten the amount of time required to achieve initial contact between the passenger's head H and the head restraining member.