Ten cases of unstable spine were treated with various surgical procedures under control of Halo apparatus and following results wen obtained. 1. Six cases of unstable cervical spine were treated with Halo apparatus and were able to obtain solid fusion for permanent stability. 2. Three cases of tuberculous kyphosis were corrected with halo-pelvic hoop on, and were able to obtain mean correction angle of 42 (65%) with little danger. 3. With halo on, staged operations such as anterior and posterior osteotomy, gradual distraction, anterior and posterior fusion of the spine for correcting deformity were carried out securely. 4. Average duration of halo application was eight weeks, no more twelve weeks, and there was no irreversible complication with halo apparatus per se.