A resin film comprising (A) an epoxy resin having two or more glycidyl
groups in a molecule, (B) an epoxy resin curing agent, (C) a
thermoplastic resin, and (D) a filler, wherein the filler content in at
least either one of the surface regions on the cross-section of the film
is less than the filler concentration in the central region. The resin
film has not only toughness but also fire retardancy, high interlayer
adhesion strength and good processability of metal plating.