We have developed a new gait assisting device for patients with hemiplegia, by which a single therapist alone can work with : 1) swing of the paretic limb, 2) stance of the paretic limb, and 3) alternate lateral weight-shift during gait. This device (ASSWS : Assistance of Swing, Stance and Weight Shift) imitates the kinesiological complex (patellar ligament, quadriceps, iliotibial ligament and gluteus maximus) to maintain a standing posture for the lower extremities. We compared the results of a gait analysis using a motion analyzer for gait with ASSWS and gait without ASSWS. With ASSWS, the walking speed was faster, stride length was longer, and stride duration was shorter. No differences in floor reaction force were identified. With ASSWS, the flexion peak of the hip joint became larger and the knee joint was in a more flexed position throughout the walking cycle. Also, the joint moment of hip extension, hip flexion and knee extension all increased with use of the ASSWS.