The purpose of this research is to investigate the actual wearing conditions of working uniform and identify problems for the aircraft mechanic. For this study, questionnaire surveys were conducted dividing according to styles of clothing; one-piece and two-piece styles. Subjects were 343 men working in flight line. Questionnaire of 159 two-piece styles and 184 one-piece ones were used in analysis. The results of the study are as follows; The result about wearing each type of working uniform showed that the two-piece one is always as the air force uniform, whereas the one-piece one is worn only a few times. They felt inconvenience during all operations except in the sitting position, crawling position, and positions in which they were using tools. Accordingly, the result of the functionality reported dissatisfaction on all question items. Therefore, uniform of two-piece style achieved better results on all questions related to motional flexibility and functionality. Questions on changes to finishing methods showed that each airline employed different methods for both two-pieced and one-pieced uniforms. The answers about the unstitched or worn-out parts of the two-piece garments showed that pants were unstitched on the inner seam of the trouser leg and hip regions, but the upper one was not. In case of the one-pieced uniform, the parts of wearing out is the seam of hip and the unstitched parts are knee region and hem line of pants. Questions concerning their satisfaction with the material of uniforms indicated a high rate of dissatisfaction, particularly in its ventilation and absorbency. Questions concerning the preferred design of working uniform indicated a preference for two-piece uniform rather than one-piece ones.