This study aims to improve the uniform functionality of the workers who work in Electric Technology Division, Korea Railroad Corporation. Former study of questionnaire survey was taken to examine the current state of wearing working clothes for the workers. Based on the results of the former study, an experimental clothes, the functionality of which has improved in terms of design, materials, and patterns, was created, and existing working clothes and the treated experimental clothes were compared through simulation wearing evaluation comprising appearance, activity adaptability, quantitativeness, and on-site adaptability evaluation comprising appearance and activity adaptability. The followings are the results of the study: Simulation wearing evaluation is composed of 5subjects and 11experts specializing in costume, and as a result of evaluation the experimental clothes were evaluated superior to the existing working clothes in all items. On-site adaptability evaluation was conducted by workers in the Electric Technology Division, who are the subjects in this study. In that evaluation, the experimental clothes were also evaluated superior to the existing working clothes in all items. While the five subjects who participated in the simulation wearing evaluation move, the quantitative evaluation measured the distance of location transfer of the back length in the jacket and the distance of location transfer of the back waist in the trousers. As the distances in the experimental clothes were measured shorter than the distances in the existing working clothes, the subjective evaluation results are objectively supported.