PURPOSE: To materialize a convenient and easy-to-use container from which a fluid substance is taken out in small quantities by attaching a conduit pipe which is connected to a mouth part of a lid and an inner bag which wraps the conduit pipe in an elastic outer container which is equipped with a check valve.
CONSTITUTION: For a duplex container which involves a bag equipped with a conduit pipe, in an elastic outer container 1 equipped with a check valve 3, a conduit pipe 4 which is connected with a mouth part 81 of a lid 8, and an inner bag 2 which wraps the said conduit pipe 4 are attached. The inner bag 2, of which the material is a synthetic resin, and of which the bottom part has a V-shape, wraps the conduit pipe 4, and the mouth part is attached to the upper part of the conduit pipe 4 or the mouth part of the outer container 1. The attaching method is to screw the mouth part of the inner bag 2 in the upper part of the conduit pipe 4, or to press-fit the mouth part which is fitted on a ring-shaped protuberance. For the conduit pipe 4, a vent hole is provided on the upper part. In the case of the outer container 1 equipped with a pump P, the conduit pipe 4 which is connected to the mouth part 81 and a bellows which wraps the said conduit pipe 4 are attached in the outer container 1. In the case of an outer container 12 which is made of a paper pack equipped with a vent hole 32, a bag 2 with a strow-shaped mouth part 82 equipped with a notch C is placed in the outer container 12, and the straw-shaped mouth part 82 is projected to the outside of the outer container 12.