To provide an epoxy resin composition for semiconductor sealing, giving a cured product having flame retardancy without using a flame-retardant such as a halogen compound and an antimony compound.

The epoxy resin composition contains an epoxy resin, a hardener and an inorganic filler, wherein the epoxy resin is obtained by reacting a phenolic resin expressed by formula (1) (wherein n is an average repeating number) provided that n1.0 and n3.0 with 3-10 times mol of an epihalohydrin based on a hydroxyl equivalent of the phenolic resin.