Abstract: A seat back panel includes a panel main body and a separate panel. The panel main body is disposed at a posterior portion of a seat back of a vehicle seat. The panel main body structures a portion of a main body portion of a seat back frame. An aperture is formed at a location of the panel main body that opposes a dorsal region of a seat occupant. The separate panel is attached to the main body portion and closes up the aperture. At a time of rear-end collision of the vehicle, the separate panel receives a load from the dorsal region of the seat occupant and relatively displaces toward the rear side of the seat back with respect to the panel main body.