PURPOSE: To obtain the titled composition, containing an epoxy resin, curing agent, the first silicone polymer having functional groups at the both ends and second polymer having functional groups in the side chains as essential components, having low elastic modulus as well as linear expansion coefficient and useful for sealing semiconductors.

CONSTITUTION: A composition containing (A) an epoxy resin, (B) a curing agent, e.g. phenol novolak resin, etc., (C) the first silicone polymer, preferably aminosilicone intermediate having ≥1,000 amine equivalent or epoxysilicone intermediate having functional groups, e.g. amino group, carboxyl group, epoxy group, hydroxyl group, pyrimidine, etc., and (D) the second silicone polymer having functional groups in the side chains as essential components. The total of the first and second silicone polymers added is preferably 10W50pts.wt. based on 10pts.wt. epoxy resin.