A fiber reinforced composite material having high interlaminar toughness and compressive strength under wet heat conditions, as well as an epoxy resin composition for production thereof and a prepreg producible from the epoxy resin composition is described. The prepreg includes at least constituents [A], [B], and [C] as specified below and reinforcement fiber, wherein 90% or more of constituent [C] exists in the depth range accounting for 20% of the prepreg thickness from the prepreg surface: [A] epoxy resin; [B] epoxy resin curing agent; and [C] polymer particles insoluble in epoxy resin.