To obtain a thermal insulation block for floor heating which can be used even in a wet place and in which the temperature can be controlled for each block by laying a planar self temperature controlling heating element in an outer frame of fiber reinforced concrete and then filling the outer frame with aerated concrete to produce the thermal insulation.

A self temperature controlling heating element 3 is laid in a thin square box type forms of fiber reinforced concrete 1 having high bending strength and then the forms is filled with highly thermal insulating aerated concrete 2 to complete a light and strong thermal insulation block for floor heating. The thermal insulation blocks are laid on the mortar setting bed of a building, and finished with a flooring material. In case of bath room or porch, a ceramic tile 4 or a stone is laid on the surface of the block. Since the floor heating block is made of concrete block, waterproofing is facilitated in bath room or porch where water is used and bath room or porch can be floor heated. Furthermore, high energy saving effect can be achieved because the block has high heat storage capacity.