To smoothen the opening and closing without one of vessels or the lid of a vessel or the like being separated, and facilitate the disassembling.

In an opening and closing device for vessel in which shaft holes 12 provided on opposed side walls 11 of one half vessel body 1 are fixed shaft holes 22 provided on the side walls of the other halve vessel body 2 by clips 3, respectively, whereby the half vessel bodies 1, 2 are mutually joined in such a manner as to be turnable, the clip 3 is formed of a head part 31 making contact with the side wall 11 of the one half vessel body 1, a shaft part 32 continued to the head part 31, and a tip-side locking part 33 to be engagingly locked by the side wall 21 of the other half vessel body 2. The locking part 33 has an outward swollen curved surface having a width larger than the diameter of the shaft holes 12, 22, and it is formed in such a manner as to be laterally contracted by elastic deformation when passed to the shaft holes 12, 22, and returned to the original state after insertion.