PURPOSE: To provide a sterilization device having a heat exchanger in which mixing of bacilli or the true fungi or the like can be set as in surrounding atmosphere or a mixing degree as found in the surrounding atmosphere or less, its operating expenditure is less under a minimum consumption of energy and a uniform heating can be carried out.

CONSTITUTION: In a rotor 2 in which corrugated laminated honeycomb structures of heat exchanging elements are formed into a cylindrical shape, a frame 3 is arranged at an intermediate position facing against an indoor side in such a manner that it may occupy its horizontal orientation. A feed screw 4 fixed under a condition in which a hot air injection nozzle 6 is threadably engaged with it is rotated by a rotary driving means 5. The hot air injection nozzle 6 is arranged at a gas returning side of the rotor 2 and it is moved axially as the feed screw 4 is rotated. Heat air heated by an air heater 8 is supplied to the hot air injection nozzle 6. A hot air acceptor is arranged at an outdoor side of the rotor 2 at a location where it may correspond to a lotus of reciprocating motion of the hot air injection nozzle 6.