Provided is a medical multilayer vessel with gas barrier performance and transparency suitable enough for medical packaging materials which are subject to heat sterilization. The medical multilayer vessel concaining layer (X) contains a water vapor barrier polymer that contains polyolefin resin(s), and a gas barrier layer (Y) composed of a polyamide resin composition (P), the polyamide resin composition (P) contains 10 to 45% by mass of polyamide resin (A) that contains a diamine unit with a content of a structural unit derived from xylylenediamine of 70 mol% or more, and a dicarboxylic acid unit with a content of a structural unit derived from a straight-chain aliphatic dicarboxylic acid having 6 to 18 carbon atoms of 70 mol% or more； and,90 to 55% by mass of a poly(hexamethylene isophthalamide)/poly(hexamethylene terephthalamide) copolymer (B).
