The mushroom, Sarcodon aspratus was tested for its possibility of being a health food against corpulence. The mushroom powder was fed to rats with high-fat diet-induced corpulence for 6 weeks. To measure its effects, various factors such as obesity index, serum lipid, and organ weight were analyzed and compared. The group fed a high-fat diet showed a significant increase in the levels of triglyceride, total cholesterol and LDL-cholesterol in serum. However, this increase was not shown in the group fed mushroom powder. The R$ddot{o}$hrer index (one of many obesity indexes) was higher in the group fed a high-fat diet compared to that of control group. However, there was a significant decrease in the R$ddot{o}$hrer index in the group fed with mushroom powder. Especially, the increased ratio of liver to body weight was observed in the group fed a high-fat diet compared to the control group. These results suggest that the significant changes in obesity index and organ weight in the group fed with mushroom powder are due to the decreased level of serum triglyceride. Thus, there is a possibility for Sarcodan aspratus to become a heath food that can prevent diseases related to corpulence.