An epoxy resin composition comprising (i) a compound having at least two epoxy groups in a molecule as a main component, (ii) a fluorene skeleton-bearing, silicone-modified phenolic resin as a curing agent, and (iii) an organophosphorus compound, amine compound or imidazole compound as a cure accelerator cures into an elastomeric product having a low elasticity, toughness and low dielectric properties.