To dispense with a cooling fan and a power source, and to miniaturize an electric appliance by providing at least a heat exchanger and a heat storage material which is brought into contact with the heat exchanger, and realizing the heat exchange of the steam with the heat storage material through the heat exchanger to liquefy the steam.

The steam introduced from an inlet tube 2 is diffused by a distributor 1, and fed into tubes comprising a heat exchanger 5. The steam fed in the heat exchanger 5 is moved downward while exchanging the heat with water which is the heat storage material 2 through a radiation fin. Water condensed through the heat exchange is collected by a collector/distributor 3, and discharged from an outlet tube 4. The heat storage material by phase change of material stores the thermal energy to be obtained when the solid is changed into liquid. When the heat storage material by phase change of material is used as the heat storage material 6, the heat exchanger 5 can keep the steam below the liquefying temperature for a long time, and the steam treatment can be further efficiently achieved. A cooling fan, a power source, or a power source cord can be dispensed with, and the structure is simplified.