PURPOSE: To prevent the occurrence of the thermal strain in a seal for preventing leakage of fluid between an end face and a housing owing to contact of a rotary type heat-exchanger with the end face of a heat accumulating core.

CONSTITUTION: A cross arm seal 4 is brought into contact with the end face of a core 1 across the high temperature side 1H and the low temperature side 1L of a heat accumulating core 1. Opening-in taper surfaces 52 and 62 are formed at semi-arcuate outer peripheral seals 5 and 6 at an outer peripheral seal part 2 formed at the end face of the outer periphery of the core 1. The outer seals are brought into contact with a cross arm seal 4 at cardinal points 51 and 61 and arms 10 and 11 extending from the outer peripheral seals 5 and 6 along the cross arm 14 are bound with each other on a line 0, passing the cardinal points 51 and 61, by means of a C-type metal fixture 14.