To provide a hot water piping system floor heating device to dissolve various problems in a usual hot water piping system floor heating device.

A floor heating device is composed of plural sets of elastic hot water piping 2 arranged at mutual intervals on the upper face of a flat floor substrate 5; and self-leveling materials 3 laminated on the floor substrate 5. The hot water piping 2 has a pipe wall circular in section, and the outside diameter of the piping 2 is smaller than the thickness (t) of the self-leveling material 3, and the hot water piping 2 is buriedly provided inside the layer of the self-leveling material 3. The self-leveling material 3 is filled up in a domain among the hot water piping 2.