The purpose of this study is investigate the feature of the body shape of obese males and to propose a new apparel sizing system considering the body size of obese men through an the analysis of the body measurement of obese men in their twenties as reported in the 'Fifth Korean National Physical Standard Reports'. For this study, a new apparel sizing system for casual wear was proposed for obese men in their twenties after a body measurement of 159 obese men in their 20s with a BMI of 25 and over as reported in the 'Fifth Korean National Physical Standard Reports' conducted by SIZEKOREA. This study sought to investigate the features of obese men's bodies by comparing the body shape between obese men and ordinary men. The result of shows that width, depth and circumference items influencing the width size when producing clothes are larger in the case of an obese body shape than an ordinary body shape, and that the stature, total length, arm length and outside leg length influencing the length size are similar between an obese body shape and an ordinary body shape. Therefore, it was confirmed that an apparel sizing system specializing in clothes for obese customers is required. As a result of this study of the features of body shape, the control dimensions for such an apparel sizing system were determined to be the stature and chest circumference of upper garments and the stature and waist circumference(omphalion) for lower garments. The interval between the sizes was 5cm for the stature and was irregular for the chest and waste circumference. Consequently, 8 sizes were proposed for upper garments and 9 sizes were proposed for lower garments.