This cryogenic energy recovering gas vaporizer is equipped with: a casing in which an intermediate medium can be sealed; an intermediate medium evaporation unit that performs heat exchange between a liquid-phase intermediate medium and a heat source medium in order to cause at least some of the intermediate medium to evaporate; a low-temperature liquefied gas evaporation unit that performs heat exchange between the intermediate medium evaporated by the intermediate medium evaporation unit and low-temperature liquefied gas in order to cause the low-temperature liquefied gas to vaporize; and a refrigerant cooling unit that is disposed within the casing, and performs heat exchange between the intermediate medium and a refrigerant in order to cool the refrigerant.