To provide a medical vessel endurable to high pressure steam sterilization of a temperature not less than 120°C.

In this heat resistant medical use vessel, an outer layer of a vessel wall is composed of a mixed resin containing low density polyethylene by 30 wt.% or less in linear polyethylene obtained by using a metallocene catalyst having density in a range of 0.935 to 0.950 g/cm3. An intermediate layer of the vessel wall is composed of a mixed resin containing low density polyethylene in a range of 40 to 70 wt.% in linear polyethylene obtained by using a metallocene catalyst having density in a range of 0.935 to 0.950 g/cm3. An inner layer of the vessel wall is composed of a mixed resin containing polypropylene in a range of 25 to 50 wt.% in linear polyethylene having density in a range of 0.910 to 0.930 g/cm3. In this case, a thickness of the outer layer falls within a range of 40 to 75 μm, a thickness of the intermediate layer is not less than two times the thickness of the outer layer, and a thickness of the vessel wall is set not more than 400 μm.