A pulse tube refrigerator includes a compressor, a first heat exchanger, a first regenerator, a first cold head, a first pulse tube, a first radiator, a second regenerator, a second cold head, a second pulse tube, a second radiator, an orifice and a buffer tank which are connected in series. A first cooling part consists of the first heat exchanger, the first regenerator, the first cold head, the first pulse tube and the first radiator. A second cooling part consists of the first radiator, the second regenerator, the second cold head, the second pulse tube and the second radiator. The first radiator forms not only the radiator of the first cooling part, but also the heat exchanger of the second cooling part.