Building fires can lead to loss of human lives and economic damage, as well as secondary damage due to collapsing buildings. Consequently, fire resistance performance of structural members has been garnering considerable interest in Korea. Fireproof structures are applied on the basis of the specification design. However, recent research results that focus on application of performance design have been published through a research project by the Ministry of Land, Infrastructure, and Transport. Therefore, in this study, composite beam specimens coated with fire-resistant material were manufactured, and fire resistance tests were conducted for 3 h. Additionally, finite element analysis was performed under the same shape and conditions to verify the reliability of the fire resistance analysis, which was conducted by varying the thickness of the fire-resistant coating.