This study aims to compare the ease of men's slim pants patterns, and to analyze the fit and appearance through the 3D virtual garment system. The study selected four educational materials and one industrial pattern of slim pants for a total of five items. The CLO 3D Modelist program was utilized to carry out the appearance evaluation through virtual wearing and opacity, and a comparison was performed regarding the clothing pressure when the virtual model was standing and walking. The results of our comparison of the patternmaking for slim pants showed that pattern C pants had the greatest ease on the waist circumference, while B pants showed no ease. The C and E pants also had the most ease on the hip measurement. In the appearance evaluation, A pants received the most favorable results, followed by D, E, B, and C, in descending order. The clothing pressure appeared to be mainly red on the waist, crotch, and hem when standing in all pants, so the clothing pressure was high. While walking, the stress appeared to be different for the left and right parts of the body, and the most significant difference was observed on the thigh area.