PURPOSE: To efficiently condense and recover water by installing a means to detect the state of air immediate after it has passed evaporation medium and a controlling means to control evaporation affecting factors based on the detected state of air.

CONSTITUTION: A fan driving means 62 to drive a fan 56 for circulation, a condenser 49 to control heat radiation of a first heat radiating part 47, an expansion valve 50 to control a heat absorption of a cooler 46, and a belt driving means 63 are connected with a controller 58. The controller 58 controls operation of at least one means based on temperature detected by a temperature sensor 57 and adjusts evaporation amount of water in wastewater. As another means to adjust evaporation affecting factors, means such as heating means of the endless belt 45, cooling means, heating and cooling means to heat and cool wastewater in a raw liquid tub, etc., are available. In this way evaporation efficiency is improved.