We report the diagnosis and treatment process of a patient who underwent CyberKnife radiotherapy with diagnosis of optic nerve sheath meningioma (ONSM) to emphasize visual field recovery with an early treatment. A 46-year-old woman pre- sented with puffiness, discomfort, and enlargement in right eye. Right sided proptosis and optic disc edema were detected as accompanying findings. Visual acuity was 20/20 in both eyes. Blind spot enlargement and mild peripheral constriction were found on the right side of visual field test. The diagnosis was made on the basis of clinical and radiological findings. Magnetic resonance imaging demonstrated an ONSM. The lesion was treated by three fraction stereotactic CyberKnife ra- diation therapy with dose of 19.5 Gy. Visual acuity was preserved and visual field was completely recovered after 6 weeks of follow-up. Due to its typical clinical and radiological findings, ONSM can be diagnosed without tissue biopsy. In progressive cases, optic nerve functions may recover by CyberKnife radiation therapy performed before development of significant visual loss. However, patients should be observed for radiation complications.