To simplify a structure, facilitate maintenance inspection, reduce in size and improve heat exchanging efficiency by a method, wherein a rotary type heat storage body is rotated by imparting a heat storage body with a circumferential force by the spiral circumferential flow of gas sent out from propeller fans.

A rotary type heat storage body 1 rotates freely, while being supported by bearings 3a, 3b. The heat storage body 1 is formed of flow passages defined into small compartments by bulkheads so as to conduct gas to flow into an axial direction and so as not to mix two series (high-temperature series A and low-temperature series A') of gas by the partitioning guides 4, 4b. In this case, both ends of the heat storage body are opened to cause the gas by fans 5a, 5b to flow into the body 1 from one end and flow out of the body 1 through the other end. The flow of gas near the outer periphery of the heat storage body 1 among the flows of gas, sent out of the fans, flows directly into the heat storage body as shown by the arrow B, B' in a diagram and the balance of the flows of gas are collided against the partitioning guides 4a, 4b to flow into the heat storage body 1, after changing the flow direction thereof as shown by the arrow C, C'. As a result, the circumferential component of the spiral flow generates sufficient torque in the heat storage body.