HUMIDIFIER

PROBLEM TO BE SOLVED: To facilitate cleaning by adding a water soluble polymer into water to be heated and washing with water without hardening scale regardless of the quality of water. SOLUTION: When a water tank 1 filled with evaporation water 2 is set on a water receiving section 3, the evaporation water 2 flows to the water receiving section 3 thence flows through a water passage 5 to an evaporation pan. When the water tank 1 is loaded, a constant quantity lever 12 is moved downward by the weight of the water tank 1 to press the sealing part 10 of a container 9 filled with polyethylene glycol 11. A fixed quantity of polyethylene glycol, i.e., about 1/100,000 wt.% of water, is dripped onto the drain pan 3 through a duct 13. Polyethylene glycol is dissolved into water and dispersed uniformly into the evaporation water 2 in the water tank 1.