There is provided a vehicle seat including a seatback frame including: a first base member formed of a thin plate member made of resin; a second base member formed of a thin plate member made of resin and disposed facing the first base member; a pass-through portion that is formed to at least one of the first base member or the second base member, and that enables insertion of an injection nozzle for injecting a foaming liquid for a foamed body; and a core section that is configured by the foamed body, that is disposed between the first base member and the second base member, and that is adhered to the first base member and the second base member.