PURPOSE: To obtain the title composition which can give a film improved in toughness without detriment to its appearance by mixing a bisphenol epoxy resin with a curing agent and a specified copolymer.

CONSTITUTION: An aramid/polybutadiene/acrylonitrile block copolymer (a) having phenolic hydroxyl groups of the formula [wherein x=3-7; y=1-4; y/(x+y)=0.1-0.3; z=5-15; m=1-400; n=1-400; n/(m+n)=0.01-0.50; 1=1-50; Ar1 and Ar3 are each a bivalent aromatic group; and Ar2 is a bivalent group having a phenolic hydroxyl group] is dissolved in an organic solvent (b), and reacted by heating with a bisphenol epoxy resin (c) to obtain an epoxy resin-modified product. This product is mixed with component (c) and a curing agent (d), and the obtained mixture is melt-kneaded and ground to obtain the title composition containing component (c), component (d) and component (a).