To provide a sealing structure for preventing gas from passing through a gap formed between a sealing shoe and a stator inner cylinder upon low loading.

In a rotary heat exchanger, a stator includes an outer cylinder, a top plate 17, and an inner cylinder 7 having a bottom plate 18 with a heat exchange element mounted between both cylinders. A main shaft 11 supported rotatably on a bearing passes through the inner cylinder 7 in the direction of a central shaft. Opposite ends of the main shaft 11 are fixed to upper and lower hoods 3, 4 with a cylindrical expansion sleeve 15 surrounding the main shaft 11. An external end of the sleeve is mounted on the hoods 3, 4 with an inner end of the same mounted on a ring shaped sealing shoe 16 engaged slidably with the inner cylinder top plate 17 and the bottom plate 18. A ring shaped groove 23 is provided in a surface opposing to the inner cylinder top plate of the sealing shoe 16 and to the bottom plate 18, along which groove a sealing ring 24 is mounted with an inner end thereof making contact with the inner cylinder top plate 17 or the bottom plate 18 and with an outer end entering the groove having a gap between it and a bottom of the groove 23.