This invention provides an insulating resin composition for a multilayer printed wiring board, which is excellent in desmearing properties in a multilayer printed wiring board production process, and an insulating resin sheet with a base material. There are also provided a highly reliable multilayer printed wiring board, which has excellent thermal shock resistance, moisture absorption/soldering heat resistance and other properties, using the insulating resin composition for a printed wiring board, and a semiconductor device. The resin composition is characterized in that it comprises, as indispensable components, (A) an aminosilane coupling agent, (B) silica having an average particle diameter of not more than 2.0 [mu]m, (C) an epoxy resin, and (D) a phenoxy resin, the content of the epoxy resin (C) is not less than 14% by weight and not more than 79% by weight based on the resin composition, a cured product of the resin composition has a coefficient of linear thermal expansion of not more than 35 ppm at a temperature in the range of 25 DEG C to 150 DEG C and a glass transition temperature (Tg) of 190 DEG C or below, and the lowest dynamic viscosity of the resin composition is not more than 2000 Pas.