An object of the invention is to provide an insulation circuit board with high insulation reliability and a related technology that uses this insulation circuit board. An insulation circuit board (12) according to the invention includes: a metal base plate (1); an insulation layer (2); and a conductive circuit (4) formed on the metal base plate (1), with the insulation layer (2) therebetween, wherein the insulation layer (2) is formed by lamination of a plurality of layers that includes at least: a composite insulation layer (2a) that forms a surface boundary with the conductive circuit (4) and includes an inorganic filler (8) dispersed in an insulation plastic (7); and a simple plastic insulation layer (2b) that includes no inorganic filler (8).