PURPOSE: To inhibit the reduction in drying capabilities at a low temperature and to save the consumption of electric power by a capacitor which warms the air cooled and dehumidified with an evaporator and a gas-heating source heating the coolant introduced into a condenser.

CONSTITUTION: Air that flows into a unit chamber 30 is cooled and dehumidified when passing through an evaporator 16. Drain generated in the dehumidification is dropped onto a drain plate 23 and then discharged to the outside. Air cooled and dehumidified with an evaporator is then introduced into a condenser 19 and warmed and dried here to form a warmed air. This warmed air is blown out into a bathroom 27 from the outlet with a sirocco fan 34 to dry the inside of the bathroom. Then, concerning the unit outside of the bathroom 26, the evaporator 16 is cooled at the cooling to conduct the function of heating the condenser 19 at a coolant heating unit 38. While, at low temperatures, the flow rate adjusting valve 20 opens to increase the combustion volume of a burner at a heating unit 21 and, at high temperatures, the same valve closes to cause the reverse effect.