A rotary heat engine having a cylinder and a rotor having a rotating shaft rotatably placed in the cylinder. The cylinder has a heat receiving section for supplying heat to the inside of the cylinder and a heat radiating section for radiating heat from the inside. The engine also has an engine section body and an operation liquid storage section. A vaporized gas supply channel and a gas recovery channel communicating with the inside of the cylinder are provided, respectively, on the heat receiving section side and heat radiating section side of the cylinder in the engine section body. The operation liquid storage section is between the vaporized gas supply channel and the gas collection channel in order to aggregate and liquefy recovered gas and is installed such that both channels fluidly communicate with each other. Also, the operation liquid storage section has a heat insulation dam provided with a through hole for preventing backflow of fluid flowing inside.