The present invention provides: an insulating substrate or
metal-clad laminate able to sufficiently reduce or prevent negative warping of a
semiconductor device; a printed wiring board that uses the insulating substrate or
metal-clad laminate; and a
semiconductor device. The insulating substrate is composed of a cured product of a laminate including one or more fibrous base material
layers and two or more resin
layers, in which the outermost
layers on both sides is the resin layers. At least one of the fibrous base material layers is shifted towards the first side or a second side on the opposite side thereof with respect to the reference position, namely the dividing position at which a
total thickness of the insulating substrate is equally divided by the number of the fibrous base material layers and each divided region having the thickness is further equally divided by two. The fibrous base material layers are not shifted in different directions. It is possible to produce a printed wiring board by using, as a core substrate, a
metal-clad laminate containing the insulating substrate. Also, it is possible to produce a
semiconductor device by mounting a semiconductor element onto the printed wiring board.