The power recovery system includes: a Stirling engine; and a vaporization device that stores a liquid therein in such a manner that the liquid is kept in contact with an upper portion of a cylinder and vaporizes the liquid by supplying the cold heat of the liquid to the upper portion of the cylinder. The vaporization device includes a liquid container which stores the liquid therein in such a manner that the liquid is kept in contact with the upper portion of the cylinder, and an outer container embracing the liquid container and defining a space portion around the liquid container. The space portion communicates with the liquid container and an exhaust vent. Gas vaporized in the liquid container passes between the liquid container and an outer wall surface of a heat insulating material during passage thereof from the liquid container to the exhaust vent through the space portion.