A vehicle seat is capable of being shifted to a walk-in state without side support parts or a tilt part hindering the seat back from folding forward. A seat includes a seat cushion, a seat back, and a leg rest part. The seat is provided with side support parts at left and right sides of an occupant, and a tilt part that moves a front portion of the seat cushion upward and downward. The seat is further provided with a detecting part that detects a state of the seat back, and a control unit that causes at least one of the side support parts and the tilt part to transit from a deployed state to a housed state when the detecting part detects that a forward turn of the seat back is started.