Lid, method of producing lid, and molds for forming molded pulp

A method of producing a lid, the lid comprising a top plate including an abutting part, and a side wall including an undercut part provided below the abutting part and extending downward from a periphery of the top plate, the lid being produced using molds for forming a molded pulp, the molds including a papermaking mold and a drying mold, wherein

• the papermaking mold for forming a lid is provided with one or more suction holes at a level corresponding to a level of the undercut part to be formed on an inner surface of the side wall, the method comprising
• forming the undercut part in a convex shape on an inner surface of the side wall by suctioning the side wall using the suction holes when a molded article of the lid is at least in any one of a state that is before being heated and dried, a state that is under heating and drying, and a state that is immediately before being released.