An epoxy resin composition for encapsulating a semiconductor chip according to this invention comprises (A) a crystalline epoxy resin, (B) a phenol resin represented by general formula (1): wherein R1 and R2 are independently hydrogen or alkyl having 1 to 4 carbon atoms and two or more R1s or two or more R2s are the same or different; a is integer of 0 to 4; b is integer of 0 to 4; c is integer of 0 to 3; and n is average and is number of 0 to 10, (C) a (co)polymer containing butadiene-derived structural unit or its derivative, and (D) an inorganic filler in the amount of 80 wt % to 95 wt % both inclusive in the total epoxy resin composition.