To obtain a resin composition for composite materials imparting excellent yield strength and impact resistance against large deformation to composite materials, an intermediate material for composite materials, and a composite material having excellent mechanical properties.

The resin composition for composite materials comprises 5-30 wt.% epoxy resin having 700-7,500 epoxy equivalent and containing a reaction product of a halogen-free isocyanate-modified epoxy resin having 200-450 epoxy equivalent with a polyhydric phenol, 1-10 wt.% epoxy resin curing agent and the balance of an organic group-containing polymer and/or the balance of an additive, and has 5,000-1,000,000 Pa.s viscosity at 30°C.