To provide a warm air heater capable of surely spreading minus ion, of which an existence time from generation to extinction is short, into a room so that a dweller can sufficiently get the effect of minus ion.

In this warm air hater comprising a heating part 3 in a main body 1 of the heater, and releasing the heat generated from the heating part 3 into the room through a warm air blowing-out port 8 formed on a front face of the main body 1 by a warm air blower 7, a louver 9 of the warm air blowing-out port 8 is coated with a coating material 10 prepared by adding and kneading granulated particles of minus ion generating substance 10a such as tourmaline, a dispersant 10b for uniformly distributing the particles of the minus ion generating substance 10a in the coating material 10, and an additive agent 10c promoting the generation of minus ion.