To provide a plate material for heating capable of heating a ceiling in a room besides heating a floor plate by heating the plate material for heating using true jade powder radiating far infrared ray.

This plate material for heating is manufactured by mixing true jade powder radiating far infrared ray, in a natural wood material and shaping the same in the form of plate. This floor heating device for a building is constituted by placing a heat insulating mat 3 under a floor of the building, mounting a heat retaining block 4 on the heat insulating mat, then setting a heat conductive plate 5 on the same, arranging a hot water supply pipe 7 in a piping groove of the heat conductive plate 5, and placing the plate material for heating on the same.