Benchmark experiments for the validation of secondary-gamma-ray data are conducted for iron and Type 316 stainless steel (SS316) shield assemblies bombarded by deuterium-tritium neutrons. Gamma-ray spectra and heating rates for both threshold and capture gamma rays are measured. With the present experimental data for gamma rays, a set of benchmark data for iron and SS316, including neutron energy spectra in entire energies and various dosimetry reaction rates, is completed for the first time. Secondary-gamma-ray data in JENDL-3.1, JENDL-3.2, JENDL-Fusion File, and FENDL/ E-1.0 are tested by benchmark calculation of the experiments. As a result, larger gamma-ray-production cross sections for threshold reactions in JENDL-3.1 and JENDL-3.2 and an inconsistent energy balance of the (n, γ) reactions in JENDL-3.1 are found. From the viewpoint of fusion engineering, the first priority in evaluating secondary-gamma-ray data should be conserving the energy balance. A rigid energy balance in both the JENDL Fusion File and FENDL/E-1.0 is confirmed for both threshold and capture gamma rays. The JENDL Fusion File and FENDL/E-1.0 provide the highly accurate secondary-gamma-ray data for iron and SS316 needed for fusion reactor nuclear design.