This study utilized data to classify and characterize the body types of plus-size adult men aged in their 30s and 40s. Diversity is an important factor in the era of inclusive design, and discussion about size diversity to include the plus size should be accommodated. Data from 493 adult men classified as obese (with a World Health Organization criterion ≥25 BMI) were used for the analysis. The results of the study are as follows. Six independent factors were extracted using factor analysis for cluster analysis, which were then classified into five types. Type 1 (29.01%) was identified as body type I with the smallest degree of obesity. Type 2 (15.4%) was identified as body type Y with wide shoulders and a thin waist. Type 3 (14.2%) was the largest body volume (body type O), while the fourth (19.27%) identified as body type H has a large height and upper body. Lastly, type 5 (22.11%) has a long lower body and a slim abdomen, referred to as body type X. This study presents a basis for the development of various clothing sizes utilizing the body shape characteristics of plus-size men in their 30s and 40s. Follow-up research is needed to develop patterns for plus size men and to design various products.