The lumbar disorder is caused by the lifting motion in daily living. An excessive moment in the lumbar joint by extension motion cause the lumbar disorder during lifting motion. The purpose of this study is to evaluate the effect of reduction by using developed support device with a shape memory alloy. The assist moment by support device was measured by using the dynamometer. In order to evaluate the muscle load, the muscle activity was measured by using surface electromyogram. From the obtained results, the assist moment increased with increase in the number of shape memory alloy. The muscle activity decreased with increase in the number of shape memory alloy during the lifting motion. This study quantitatively showed the effect of the lumbar load reduction by using developed support device with a shape memory alloy.