The present invention relates to an epoxy resin composition for a fibre reinforced composite material, which is thermosetting resin composition where the glass transition temperature Tg of the cured material obtained by heating for 2 hours at 180.degree. C. is at least 150.degree. C., and the modulus of rigidity G'.sub.R in the rubbery plateau in the temperature region above the aforesaid Tg is no more than 10 MPa. In accordance with the present invention, it is possible to provide a fibre-reinforced composite material which is outstanding in its resistance to hot-wet environmental condition, impact resistance, and strength characteristics such as tensile strength and compression strength, and furthermore it is possible to provide a thermosetting resin composition and a prepreg outstanding in terms of their peel strength to a honeycomb core.