Design activity of International Thermonuclear Experimental Reactor clarifies intense neutron streaming from ports for neutral beam injectors. Energy spectrum of the streaming is very wide and 14 MeV neutron and gamma ray are the typical radiations. Large amount of glass fiber reinforced plastics will be used in a superconducting magnet system as an electric insulation material and a support structure, for such organic material is easy to manufacture, and light and cheap. In this report, effects of 14 MeV neutron and gamma ray irradiation on interlaminar shear strength and fracture mode are investigated using G-10CR small specimen of which configuration was proposed as a standard for evaluation of the interlaminar shear strength. A short beam test under three point bending was conducted at room temperature and 77 K. Neutron fluence of 3.91 × 1019 n/m2 was irradiated and the specimens did not show clear degradation of the strength. On the other hand, gamma ray irradiation of 1 MGy made the specimen weaker and 10 MGy caused delamination. Most of the specimens showed both of interlaminar cracking and bending fracture, but some specimens were fractured with irregular shear occurred on the planes connecting loading point and supporting points.