Abstract: The present invention relates to a heater device used for a floow material with a heater contained therein and the like within a room and a floor material with a heater contained therein, said heater device comprising an insulating sheet, a plurality of belt-shaped electrodes stood in a row side by side at intervals on an upper surface of said insulating sheet, a plastic radiant body layer formed on an upper surface of the insulating sheet and said belt-shaped electrodes and an insulating layer formed on an upper surface of said radiant body layer, and said floor material with a heater contained therein comprising a bed plate, a first resin layer formed on said bed plate, a pair of belt-shaped electrodes provided at an interval on said first resin layer, a radiant body layer formed on an upper surface of said first resin layer and the belt-shaped electrodes, a second resin layer formed on an upper surface of said radiant body layer and a dressed sheet provided on an upper surface of said second resin layer.