The non-surgical treatment for the fresh humeral shaft fracture would appeared to be not sufficient in respect of immobilization and maintenance of the contact surface of the fracture ends, which have had stimulated surgeons to perform internal fixation. This might be one of the reasons to produce non-union of humeral shaft fracture, supplemented by increasing incidence of fractures due to car and machinary accident. Authors have experienced 18 cases of non-union of humeral shaft fracture and accomplished solid union in all cases by osteosynthesis accompanied by autogenous bone graft. In detail: 1. Non-union was prevalent in the agr group of 20 to 40 and mostly in male. Site of non-union was found mostly at the lower 2/3. 2. The cause of the fracture was mainly due to the car and machinary accident. Initial treatments were surgical in 14 out of 18 cases, and 12 cases of this surgically treated group were treated within 2 days after the injury. 3. On retrospective analysis of medical records and X-ray films, probable cause of the non-union were supposed to be too early performed inadequate internal fixation and post-operative infection in the operated cases, whereas distraction of fracture ends due to poor external fixation and infection in the cases treated conservatively. 4. 16 cases of established non-union were treated by authors with rigid internal fixation and additional bone graft, and 1 case with bone graft only. 5. Authors have utilized shoulder spica or long arm cast post-operatively for 1 to 4 months. 6. Union was obtained in all cases. Developed transient radial nerve palsy in 4 cases; and neighbouring joints contracture in 2 cases, which required considerable time of physical therapy.