The purpose of this paper is to clarify the corrective effect of a weight (5kg) which is held by the patiant with mild idiopathic scoliosis. The subjects consisted of twenty-five patients (6 boys and 19 girls) whose ages ranged from 13 years to 15 years (mean, 14.4 years). Fourteen cases were of thoracolumbar scoliosis and others were of thoracic scoliosis. The change of Cobb angles, vertebral deviation and tilting of the pelvis were examined on the right side holding film and the left side holding film. Results showed that the curvatures of all the patients with thoracolumbar scoliosis were corrected when they held a weight on the convex side of their thoracic curve. Those of the r-thoracic scoliosis were corrected in the same way. But only 1-thoracic curve disobeyed this law.