A rear seat includes a support plate and a planar carpet laid between a lower part of a back lining of a seatback and a deck board located behind the seatback. The support plate is configured to support the carpet from underneath when the seatback is collapsed forward. The support plate includes a fixing plate part and a movable plate part. The fixing plate part is fixed on a back lining surface of the seatback and abuts the rear side of the carpet when the seatback is collapsed forward. The movable plate part is aligned with the fixing plate part, in the seat width direction, and is joined to the rear surface of the carpet. The movable plate part covers the seat side shield. The movable plate part abuts the seat side shield from behind, and shifts away from the fixing plate part when the seatback is reclined reward.