A dehumidifier by which the rate of heat recovery by the heat exchanger for recovering heat can be increased, the power consumption of the heater can be decreased, and by which the amount of dehumidification per a power consumption can be promoted, is disclosed. The tube includes a resin impregnated fiber preform pressed progressively along an inner wall of the tube. The strain relief device consists of a first plastic layer pre-molded on the metal braiding and the jacket and the second plastic layer over-molded on the first plastic layer.