PURPOSE: To increase the dehumidifying capacity by providing an evaporator of a heat pump and a moisture absorbent in this order in the flow direction of air.

CONSTITUTION: A dehumidifier housing the following moisture absorbent 5 and a heat pump 4 is provided by extending over both an inside 2 and an outside 3 of a chamber via an outside wall wherein the synthetic zeolite or the like comprises components of the moisture absorbent and which consists of a honeycomb-shaped rotary body capable of rotating around a rotating axis 1. The humid air in the inside of the chamber is heat-exchanged with an evaporator 6 of the heat pump to dehumidify it to some degree and furthermore the air of reduced temp. is dehumidified through the moisture absorbent 5 and returned to the inside of the chamber. On the other hand, the moisture-absorbing part is transferred to a regeneration region of the outside 3 of the chamber by rotating the moisture absorbent 5 and the hot air heat-exchanged with a condenser 7 is passed to the moisture absorbent 5 via an auxiliary heater 9 and the moistened water content is discharged to regenerate it.