PURPOSE: To prevent the floor surface of an installation spot from being affected adversely even when humidification water is spilled over or an evaporation pan of a humidifier is left unfitted.

CONSTITUTION: A humidifier is installed, which is provided with an evaporation pan which introduces a part of hot air to the lower part of an enclosed combustion type combustion device 5 and a main body 1 having a convection fan 4 where the humidifier humidifies the hot air and supplied the humidified hot air indoors. The whole device is fixed on a base 10 formed in the shape of a flat bottom pan wider than the projected plan of the main body 1. The installation of the above base 10 makes it possible to protect the surface of floor structure from being denched or discolored due to the heat of humidification hot air.