Provided are a mold which is structured so that gas can be fully discharged from a cavity and resin can be prevented from getting into a vent hole, and a method for molding a resin foam molded product using the mold. A mold (1) comprises a lower mold (2), an upper mold (4), and a core mold (3) attached to the upper mold (4). Vent holes (6) are respectively provided in wall portions (3b, 3c) of the core mold (3). Attachment members (7) are detachably attached to the outer surface sides of the wall portions (3b, 3c). The attachment member (7) has a cylindrical shape with a pore-shaped air hole that communicates with the vent hole (6), and at least part of the air hole has a smaller passage cross-sectional area than the vent hole (6). A nonwoven fabric (10) is fitted to the core mold (3) so as to cover surfaces of the core mold (3) which face a cavity. End sides of the nonwoven fabric (10) cover the wall portions (3b, 3c) and cover the vent holes (6) from the cavity side.