An epoxy resin composition for casting comprising a silica powder, a liquid epoxy resin, a polyether polyol, a liquid acid anhydride, a curing accelerator, and a core shell polymer, wherein an amount of the silica powder is from 40 to 85 % by weight per 100 % by weight of the sum of the silica powder, the liquid epoxy resin, the polyether polyol, the liquid acid anhydride, the curing accelerator, and the core shell polymer, the amount of the liquid epoxy resin is 10 % by weight or more per 100 % by weight of the epoxy resin composition, the amount of the polyether polyol is from 5 to 40 parts by weight per 100 parts by weight of the liquid epoxy resin, the polyether polyol is polyoxyalkylene diol, the polyether polyol comprises a polyether polyol having an average molecular weight of not less than 400 and less than 2500 and a polyether polyol having an average molecular weight of not less than 2500 and not more than 5000, and the polyether polyol is contained in an amount of from 50 to 90 % by weight per 100 % by weight of the sum of the polyether polyol and the polyether polyol, the core shell polymer is a polymer containing a core layer including a crosslinked polymer having the rubber property and the core layer has a glass transition temperature of 0 °C or less, the amount of the core shell polymer is from 0.3 to 10 % by weight per 100 % by weight of the sum of the silica powder, the liquid epoxy resin, the polyether polyol, the liquid acid anhydride, the curing accelerator, and the core shell polymer, and an amount of the liquid acid anhydride is such that the ratio of the number of acid anhydride groups in the liquid acid anhydride and the number of epoxy groups in the liquid epoxy resin, i.e. the number of acid anhydride groups/number of epoxy groups, is 0.5 or more and 1.5 or less. an amount of the silica powder is from 40 to 85 % by weight per 100 % by weight of the sum of the silica powder, the liquid epoxy resin, the polyether polyol, the liquid acid anhydride, the curing accelerator, and the core shell polymer, the amount of the liquid epoxy resin is 10 % by weight or more per 100 % by weight of the epoxy resin composition, the amount of the polyether polyol is from 5 to 40 parts by weight per 100 parts by weight of the liquid epoxy resin, the polyether polyol is polyoxyalkylene diol, the polyether polyol comprises a polyether polyol having an average molecular weight of not less than 400 and less than 2500 and a polyether polyol having an average molecular weight of not less than 2500 and not more than 5000, and the polyether polyol is contained in an amount of from 50 to 90 % by weight per 100 % by weight of the sum of the polyether polyol and the polyether polyol, the core shell polymer is a polymer containing a core layer including a crosslinked polymer having the rubber property and the core layer has a glass transition temperature of 0 °C or less, the amount of the core shell polymer is from 0.3 to 10 % by weight per 100 % by weight of the sum of the silica powder, the liquid epoxy resin, the polyether polyol, the liquid acid anhydride, the curing accelerator, and the core shell polymer, and an amount of the liquid acid anhydride is such that the ratio of the number of acid anhydride groups in the liquid acid anhydride and the number of epoxy groups in the liquid epoxy resin, i.e. the number of acid anhydride groups/number of epoxy groups, is 0.5 or more and 1.5 or less.