Abstract: An epoxy resin composition comprises the following components [A] to [E]: [A] epoxy resin, [B] amine-type curing agent, [C] cure accelerator, and [D] red phosphorus. The epoxy resin composition contains, per 100 mass parts for the total amount of [A], 25-45 mass parts of [A1] a liquid bisphenolic epoxy resin and 20-40 mass parts of [A2] a phenol novolac-type epoxy resin, and has a content ratio of [E] to [D] ([E]/[D]) of at least 1. Provided are a light-weight fiber-reinforced composite material that exhibits an excellent flame retardancy and mechanical properties and does not produce halogen gas during combustion, and an epoxy resin composition that has a viscosity suitable for obtaining the fiber-reinforced composite material as well as prepregs.