Cooling device, semiconductor manufacturing device, and semiconductor manufacturing method

Provided is a cooling device for cooling an object to be cooled, the cooling device being characterized by having a circulation system for circulating a refrigerant for cooling the object to be cooled, wherein: the circulation system is provided with a container which includes a region for performing heat exchange between the refrigerant and at least a portion of the object to be cooled; the refrigerant is a mixed refrigerant obtained by mixing a first refrigerant having a first boiling point and a second refrigerant having a second boiling point higher than the first boiling point; the circulation system circulates the mixed refrigerant such that the mixed refrigerant enters the container at a prescribed temperature; and the vapor pressure of the first refrigerant at the prescribed temperature is higher than the withstand pressure of the container.