A 27-year-old woman was admitted because of pain radiating through her back on neck flexion that had begun a month ago. She frequently ate raw beef liver. General physical examination revealed no abnormal findings, but she showed Lhermitte's sign neurologically. Fecal examination revealed no worm eggs. Blood cell counts showed mild eosinophilia (8.2%). The IgE level was mildly increased to 397 IU/ml (normal < 250). Cerebrospinal fluid examination showed 7 cells/microliter with 50% eosinophils. A test for anti-Ascaris suum IgG antibody was strongly positive in serum as well as in cerebrospinal fluid. Cervical MRI showed high-intensity areas in the spinal cord extending from the lower medulla to the C4 spine level on the T2-weighted images, and part of the lesion at the C3 spine level was enhanced by gadolinium. Treatment with albendazole 500 mg/day for six weeks ameliorated the Lhermitte's sign and MRI lesions, and reduced the anti-Ascaris suum antibody titers in the serum and cerebrospinal fluid. Larva migrans of Ascaris suum involving the central nervous system is considered to be extremely rare, but such cases showing mild neurologic impairment without systemic symptoms may have been overlooked.