A multilayer circuit board comprises core layers 101 and 102 made of a core material impregnated with resin, resin layers 111 and 112 interposed between the core layers 101 and 102, a wiring pattern 140 embedded in the resin layers 111 and 112. The core layers 101 and 102 have a thickness of 100 μm or smaller, whereby the entire board can significantly be thinned. Furthermore, the less strong resin layers 111 and 112 are interposed between the hard core layers 101 and 102, whereby the entire board has increased strength.