PURPOSE: To prevent the damage from occurring in a large capacity panel state heat generator even a load is applied to a panel state heat-generating plate by laminating a heat insulator on the upper part of a bottom plate, laminating the generator on the upper part of the insulator, laminating a heat conductive protective material on the upper part of the generator, and so covering with a surface material as to cover the entirety.

CONSTITUTION: A heat insulator 2 having a thickness and made of foamed urethane, glass wool, etc., is laminated on a bottom plate 1 made of a cold rolled steel plate, etc., and a large capacity panel state heat generator 3 made of an electric heater panel, etc., is placed on the upper surface of the insulator 2. A protective material 5 formed of heat conductive aluminum plate material, a copper plate material, etc., is placed on the upper surface of the generator 3, and a plurality of radiating holes 4 are opened at suitable positions of the material 5. Further, the entirety is covered with a surface material 6 such as cloth having soft surface, etc. Thus, even if a load is applied to the plate, the damage of the generator 3 therein can be prevented.