To provide a rotary type heat exchanger of which the heating efficiency is prevented from lowering by heating the entire heat exchange chamber with vapor.

A vapor supply passage 5 is connected to a jacket 3 through a rotary joint 4. A condensate storage parts 8 and 9 are attached to the ends of the jacket 3. The jacket 3 and the condensate storage parts 8 and 9 are connected through condensate introducing pipes 10 and 11 and check valves 12 and 13. Condensate discharge passages 6 and 7 are arranged at the condensate storage parts 8 and 9 and are connected to the rotary joint 4. A steam ejector 16 is connected to a condensate discharge passage 14 through a valve 21. The condensate generated in the jacket 3 flows down and is collected in the downward condensate storage part 8 and discharged out of a system from the condensate discharge passage 14 through the condensate discharge passage 6 and the rotary joint 4 when the storage part 8 is positioned upward by rotary movement.