To provide a dead body housing preserving bag for companion animal which forms a sealed bag during the preservation for a long period, suppresses the advancing of the decay of the dead body and the generation of a malodor, eliminates the remaining odor, removes a generated gas, and at the same time, prevents the leakage to the outside from occurring.

This dead body housing preserving bag for companion animal has a width and a length by which the dead body can be housed, and has an unsealable opening section at a part of the periphery, and is formed of a plastic film containing an antibacterial deodorant and a gas adsorption agent. In the housing preserving bag, a water absorbent sheet having antibacterial deodorant property is fixed at least to a dead body placing surface in the housing preserving bag, and a plastic film having gas barrier property is laminated on the external surface of the housing preserving bag. The plastic film of the housing preserving bag, and one side surface of the plastic film having gas barrier property on the external surface are made transparent, and the housing preserving bag is constituted in such a manner that the opening section is sealed at least by a double chuck.