We experienced the anesthetic management of a 39 year-old-male with hereditary spastic paraplegia (HSP) associated with pain due to pes cavus. He underwent orthomorphia ostectomy and tenodesis. Preoperative neurological examination revealed that he had slight dementia, symptoms of the pyramidal tract, lower limb bathyhypesthesia, and neurogenic bladder in addition to spastic paraplegia, and he was diagnosed as having combined type of HSP. Spinocerebellar degeneration is often accompanied with this type of HSP. To avoid the use of muscle relaxants and narcotics, we tried to induce anesthesia with inhalation of nitrous oxide (N2O), oxygen and sevoflurane (sevo). A laryngeal mask (LM) was inserted at the expiratory concentration of sevo 3.5%. Anesthesia was maintained by N2O, oxygen and sevo (2-3%) under spontaneous respiration. The patient recovered from anesthesia after the end of surgery, and the LM was removed smoothly. The patient's respiratory condition was stable, and no problems were found in the postoperative period.