Neuromyelitis optica(NMO) or Devic's syndrome is an uncommon clinical syndrome associating with unilateral or bilateral optic neuritis and transverse myelitis. It is rarely found in children and usually reported in adults with serious neurologic manifestations. We report a case of an 8-year-old girl with neuromyelitis optica whose first clinical manifestation was acute visual loss of both eyes. Initially the patient had been diagnosed with central retinal artery occlusion and optic neuritis by ophthalmologic examination, a brain magnetic resonance imaging, and cerebrospinal fluid findings. She was treated with intravenous methylprednisolone pulse therapy and heparinization. Then the treatments were replaced with oral prednisolone and warfarin. At the fifteenth day after the start of oral prednisolone tapering, she visited our emergency room for voiding difficulty and paresthesia on both legs. A spinal magnetic resonance imaging revealed increased signal intensity in T2-weighted images from cervical to lumbar level, and neuromyelitis optica- IgG(NMO-IgG) was detected in the patient's serum. After we diagnosed her as having neuromyelitis optica, intravenous methylprednisolone and nine courses of daily plasmapheresis were tried. However, the patient still had visual loss, pain, and sensory loss below the sixth thoracic dermatome, and we tried maintenance therapy with intravenous rituximab. We report our case with reviews of the related literatures.