To provide an inexpensive heater mat of high durability capable of uniformly generating heat to the entire face of the mat with a small amount of heating members.

The heating members 3 are mounted on a base member 2 of this heater mat 1. Thin and long ribbon heaters 7 are used as the heating members 3, and heating conductors of the ribbon heaters 7 are composed of belt-shaped stainless steel. Two sheets of front and rear insulating films are pressed and adhered to the heating conductor through adhesive layers. The ribbon heaters 7 are wired while bent zigzagedly, and coated with two sheets of upper and lower insulating rubber sheets 16, 17. A metallic plate 8 for transferring heat is placed on the upper rubber sheet 16, and a controller 10 is assembled to the metallic plate 8 by screws 18. A cushion member 5 joined to the metallic plate 8 is formed of a porous rubber chip aggregate.