PURPOSE: To improve the heat resistance, moisture resistance, interlaminar strength, impregnating properties, etc., of a copper-clad laminate respectively by composing an epoxy resin composition disposed to a glass base material of the four kinds of specific components and setting specific conditions in these contents and mutual reactions respectively.

CONSTITUTION: In a copper-clad laminate, a glass base material is impregnated with an epoxy resin composition and dried and a prepreg is formed, and a plurality of the prepregs are laminated while a copper foil is superposed on at least one surface of a laminate and molded integrally. The epoxy resin composition is organized while employing (A) a bisphenol A type epoxy resin, (B) a novolak type epoxy resin (C) tetrabromobisphenol A and (D) a phenol novolak resin as essential ingredients at that time. The ratio of a (C) component to the whole resin components is set in 20-50wt.%. Each (A), (B) and (C) component is reacted through a process, in which the glass base material is impregnated with the varnish of the resin composition and dried.