Abstract: The present invention provides a method of manufacturing resinous containers comprising: a preparing process in which segmental molding dies are prepared, the segmental molding dies comprising a first cavity for molding hollow bodies and a second cavity for molding auxiliary parts and a third cavity for holding the auxiliary part which communicates with the first cavity; a pre-molding process in which a resin parison is supplied between the segmental molding dies, the segmental molding dies are clamped, a compressed gas is blown into the resin parison to expand the resin parison within the first cavity and to fit the resin parison to the surface which forms an outline of the first cavity, of the segmental molding dies, the compressed gas is discharged from the resin parison, and the segmental molding dies are opened to take out a formed hollow body and a formed auxiliary part; and a main molding process in which the same process as the pre-molding process is implemented except that the formed auxiliary part i