A barrier-film forming apparatus that forms a barrier film on an inner face of a container (12) having a concave or convex portion (12a) as a processing target, including: a dielectric member (50) having a cavity sized to enclose the container (12), an external electrode (13) covering an outer circumference of the dielectric member (50), an exhaust unit installed on an end face of the external electrode (13) on a side where a mouth (11) of the container (12) is located, with an insulating member (26) interposed therebetween, and depressurizing inside of the container (12) through an exhaust pipe (14), an internal electrode (17) inserted from a side of the exhaust pipe (14) and also serving as a gas blowout unit that blows out medium gas (19) for generating a barrier film into the container (12), and an electric-field applying unit that applies an electric field for generating exhaust between the external electrode (13) and a ground electrode.