To provide a device that generates power by effectively using waste heat of cooling water for cooling the engine of an automobile.

A refrigeration cycle power generator uses a refrigeration cycle that is partially different from a normal refrigeration cycle. The generator operates in such a manner that a refrigerant liquid of a medium temperature and a medium pressure, which is stored in the refrigeration tank, is heated by cooling water for cooling an engine (at 80-85°C) to be changed into a liquefied refrigerant of a high temperature and a high pressure; the refrigerant is then squeezed and expanded by a refrigerant control valve to produce a refrigerant gas of a medium temperature and a medium pressure; a refrigerant gas turbine for power generation is rotated by the refrigerant gas of a medium temperature and a medium pressure to generate electricity; and the refrigerant gas discharged from the refrigerant gas turbine for power generation is introduced into a condenser to be cooled and changed into a refrigerant liquid of a medium temperature and a medium pressure. A pressure difference is generated in the above cycle by the heating and cooling operations, and thereby, the refrigerant gas turbine for power generation is rotated to generate power without using motive power.