A dual storage system-type fluid container in which a liquid pouring tube is securely fitted and a liquid discharging passage formed in a dispenser is easily and securely connected to the liquid pouring tube. A joint for the fluid container comprises a flexible bag (12) having a neck part (11) opened such that liquid can be poured through it and also has an outer container (13) for receiving the bag (12) with the neck part (11) supported by a mouth part (13a). The liquid pouring tube (15) having a flange part (15a) can be fitted to the mouth part (13a) of the outer container (13) with a retainer (14) placed between the tube and the mouth part. A flow passage (21a) formed in the dispenser (2) can be directly connected to the fluid passage (15b) of the liquid pouring tube (15).