A heat source fluid inlet pipe of a heat exchanger main body 150 comprises a rotation side inlet pipe 27 and a fixed side inlet pipe 23 that are integrated with the heat exchanger main body 150. A heat source fluid outlet pipe comprises a rotation side outlet pipe 26 and a fixed side outlet pipe 22 that are integrated with the heat exchanger main body 150. These pipes 22, 23, 26 and 27 are constituted into a coaxial double-piping structure 16 and the heat exchanger main body 150 is allowed to rotate with a center axis A of this coaxial double-piping structure 16 as the center.