Abstract: An epoxy resin composition which can be used as a semiconductor encapsulating resin and in which the improvement of flame retardancy can be attained by suitably adapting a crosslinked structure itself of a cured article without using any flame retardant material and without particularly highly filling an inorganic filler. The epoxy resin composition includes an epoxy resin (A), a phenolic resin (B), an inorganic filler (C) and a curing accelerator (D), wherein a flexural modulus E (kgf/mm2) at 240±20% C of a cured article obtained by curing the composition is a value satisfying 0.015 W+4.1?E?0.27 W+21.8 in the case of 30?W<60, or a value satisfying 0.30 W?13?E?3.7 W?184 in the case of 60?W?95 wherein W (wt %) is a content of the inorganic filler (C) in the cured article. The cured article of this composition forms a foamed layer during thermal decomposition or at ignition to exert flame retardancy.