This paper is to verify the fire resistance of beams made from fire-resistant(FR) structural steel by means of a full-scale loaded heat test. Because of the elements contained, FR Steel has higher strength than conventional structural steel at elevated temperatures. Its 0.2% proof stress at 600°C is equal to or greater than two-thirds the value specified at room temperature. Rockwool, ceramic fire protection, and foaming-type intumescent coating were used as fire-protection materials. The results showed that the fire-protection thickness can be reduced below what is required for conventional steel beams and that 1-h fire resistance can be obtained by intumescent coating with a lower insulation property.