To obtain the subject composition having high fluidity in molding and capable of providing a semiconductor device excellent in moldability, reliability and packaging property by combining a specific polyfunctional type epoxy resin with a polyfunctional phenol resin curing agent.

This composition comprises (A) an epoxy resin containing at least one epoxy resin selected from an epoxy resin of formula I and formula II [R is a halogen or a 1-12C alkyl; (1) is a positive integer of 1-10; (m) is 0 or a positive integer of 1-3; (n) is 0 or a positive integer of 1-4] in an amount of 20-90 wt.% in total epoxy resin and containing a crystalline epoxy resin having 50-150°C melting point in an amount of 10-80 wt. % in total epoxy resin, (B) a phenol resin curing agent containing a phenol resin of formula III in an amount of ≥20 wt.% in total phenol resin, (C) 1,8-diazabicylo(5,4,0)undecene-7 and (D) fused silica powder. The composition preferably has physical properties, ≤0.15 wt.% curing shrinkage factor in molding.