A method for forming a tantalum nitride film, which comprises supplying a gaseous nitrogen atom-containing compound, as a reactant gas and supplying gaseous t-amylimido-tris-(dimethylamide)tantalum, as a gaseous raw material, to the surface of the substrate S to thus form a tantalum nitride film on the surface of the substrate S; and a film-forming apparatus, which comprises a reactant gas supply line L4; a container 13 for liquefy a raw material; an evaporator 11 for gasify the liquefied raw material; a liquid mass flow controller 12 for controlling the amount of the liquid raw material to be supplied; and a gaseous raw material supply line L1. These method and apparatus would permit the stable supply of the gaseous raw material at all times and the improvement of the throughput of the substrate to be processed and as a result, the method and the apparatus permit the improvement of the productivity of the tantalum nitride film.