This study diagnosed difference of preference about demand performance with design of men's suit according to demographic characteristic and figured out Needs of adult man consumers for men's suit. This study is survey research. In order to collect data, a questionnaire was used. To analyze the collected data, fact analysis, $\chi^2$, ANOVA, Duncan's multiple comparisons and the rest were carried out with using SPSS 14.0. Result of this study could get as following. According to silhouette and color, there was difference to age, attainments in scholarship and preference according to job. Also young people preferred fitted-silhouette and in occasion of color, all of them preferred best black. It was no difference according to demographic characteristic in preferring pattern but preferred best solid on the whole. Demand performance of men's suit appeared by five main causes of design, practicality, comfort, appearance appropriateness, another person awareness and functional materials. And most main causes showed difference according to demographic characteristic.