Provided is a method of molding, by using a mold, a component including a metal plate and a thermoplastic resin containing a thermoplastic resin arranged on a surface on one side of the metal plate, the mold including at least a movable mold and a fixed mold including a support portion. Specifically, the molding method includes: an arranging step of arranging a premolded metal plate within the mold; a fixing step of fixing the metal plate by pressing the metal plate against the movable mold with use of the support portion; and a molding step including forming a cavity between the fixed mold and the metal plate by closing the mold, bringing the thermoplastic resin into close contact with the metal plate, and forming an exposed portion by exposing the metal plate out of the softened thermoplastic resin with use of the support portion. With this, without leakage of the thermoplastic resin, a joint region to a metal surface of another component can be reliably secured.