Provided is a method for suppressing deformation by contraction after molding of a vehicle seat member comprising a foamed resin molded body embedding a frame member. The method manufactures a vehicle seat member (1) including a foamed resin molded body (100) and a frame member (200) at least a part of which is embedded therein in which the frame member (200) includes frameworks (250), (260) extending inside the foamed resin molded body (100) along an outer shape (400) of the vehicle seat member (1) in plan view. The method comprises forming gaps (101), (101), (102), (102) along an extending direction of the frameworks (250), (260) between at least a part of the frameworks (250), (260) and a part of the foamed resin molded body (100) located on an outer side of the at least a part of the frameworks (250), (260).