In forming a TiN film on a base material (10) by a MOCVD method, a space between a showerhead (3) and a trapping member (5) is heated by a heater (2) up to a temperature at which TDMAT is thermally decomposed, or higher. Next, source gas containing TDMAT, and so on are emitted from the showerhead (3) into a chamber (1). As a result, the TDMAT emitted into the chamber (1) is thermally decomposed into TiN, carbon, and hydrocarbon by the heater (2) in the space between the showerhead (3) and the trapping member (5). Then, the TiN, carbon, and hydrocarbon move toward the base material (10). Then, the carbon and hydrocarbon are trapped by the trapping member (5). On the other hand, the TiN passes through the trapping member (5) without being trapped to reach the base material (10). As a result, a TiN film containing neither carbon nor hydrocarbon grows on a surface of the base material (10).