Abstract: The vessel for sealingly storing liquid therein comprises a cylindrical trunk member of rectangular cross-section having at least an open end and made of a laminated sheet material having a thermally bonding synthetic resin layer on the inner surface thereof and at least one end member having an axially extending flange portion having a thermally bonding synthetic resin layer on the outer surface thereof, the flange portion of the end member being adapted to be fitted in the open end of the trunk member so as to be thermally bonded thereto for forming hermetical sealing therebetween. An outwardly projecting thin axial ear portion is formed at the respective corner of the flange portion of the end member by the thermally bonding synthetic resin layer provided on the outer surface of the flange portion.