To provide a thermosetting resin compsn. which does not contain a halogen compd., is excellent in flame retardance and soldering heat resistance, can retain its characteristics for a long term, and is useful as a nonhalogen material required hereafter.

This compsn. essentially comprises 100 pts.wt. phenol novolak epoxy resin or cresol novolak epoxy resin (A), 5-50 pts.wt. maleimide compd. (B) having at least one maleimide group in the molecule, 2-20 pts.wt. arom. amine (C) having an electron attractive group in the molecule, and a phosphorus component (D) in an amt. of 0.5-5 wt.% of the sum of ingredients A, B, and C and contains nitrogen components in an amt. of 2.0-10.0 wt.% of the compsn.