PURPOSE: To obtain a solventless epoxy resin composition, excellent in impregnating properties, providing a copper-clad laminated sheet by using this composition, and excellent in solder heat and measuring resistances, etc., without any adverse effects due to the removal of a solvent.

CONSTITUTION: This solventless epoxy resin composition contains (A) a bisphenol A type epoxy resin, (B) an epoxy acrylate resin having 30-70% acrylating ratio, (C) a polymerization initiator and (D) a curing agent as essential components and is used for impregnating a prepreg. This prepreg is obtained by impregnating a glass substrate therewith, irradiating the impregnated substrate with ultraviolet rays and converting the composition into a semicured state. This copper-clad laminated sheet uses the resultant prepreg.