Provided are an anti-obesity composition, a use for a material for preventing or improving obesity, and a method for preventing or improving obesity. It was discovered that a cyclic dipeptide or a salt thereof has an anti-obesity effect. The present invention provides a novel means for preventing or improving obesity by minimizing body weight gain, minimizing the accumulation of body fat, minimizing the accumulation of visceral fat, increasing the amount of energy consumption within the body, promoting the decomposition of fat within the body, and the like.