An epoxy resin composition, including: an epoxy resin (A) represented by Formula (1); an epoxy resin (B) having an epoxy equivalent of 220 or less and having twice or more epoxy groups in a molecule than epoxy groups of the epoxy resin (A); and a photocationic polymerization initiator (C), in which: the epoxy resins (A) and (B) constitute main components; and a weight of the epoxy resin (A) is 40% or more and a weight of the epoxy resin (B) is 30% or more with respect to a total weight of the epoxy resins (A) and (B): where: R represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, or a t-butyl group; n represents an integer of 0 or more and 4 or less; and m represents an integer of 1 or more and 3 or less.