The research is purposed to help obese children to recover their physical, spiritual inferiority complex and it give them to affirmative self formation by developing training-suit which has slender effect. In order to accomplish a research problem, this research examined the effect of wearer's outward appearance with the principle and element of design and the characteristics of obesity. In order to apply consumer's demand to developing goods, this research used House of quality theory. The design ten suits(the half are made for boys) development is based on the result of House of quality, parents and obese children's interview, design element, slender effect. The design which is developed is evaluated by five specialists in order to prove it's quality though the Quad analysis which is a subjective evaluation method.