Disclosed is a liquid epoxy resin composition for sealing a semiconductor device which comprises (A) a cyanic acid ester, (B) an epoxy resin, (C) an inorganic filler, (D) a metal chelate and/or a metal salt, and at least one of (E1) an acid anhydride, (E2) a dihydrazide compound and (F) a silicone resin gel, wherein at least one of components A and B is liquid at room temperature, component E1 is liquid at room temperature, and the weight ratio of component C to the total weight of the composition, the weight ratio of component A to component B, and the weight ratio of component E1, E2 or F to the total weight of the composition except component C each ranges a specific ratio.