A 71-year-old man was admitted to our hospital, because of subacute progressive back pain and thoracic transverse myelopathy. Magnetic resonance imaging showed thickening with gadolinium enhancement of dura mater at the T1-T6 vertebrate levels. A dura biopsy specimen revealed fibrous thickening of the dura with the inflammatory changes, and diagnosis of hypertrophic spinal pachymeningitis was made. The cerebrospinal fluid (CSF) contained high titer of myeloperoxydase anti-neutrophil cytoplasmic antidody (MPO-ANCA), indicating that the antibody synthesized intrathecally. After treatment with oral prednisolone, 60 mg daily for a month, thickness of the dura and the CSF MPO-ANCA improved dramatically. This is the first report of hypertrophic pachymeningitis associated with MPO-ANCA localized exclusively in the spine. This report suggests that intrathecal MPO-ANCA synthesis is an index of disease activity as well as a diagnostic hallmark. Early corticosteroid therapy is recommended in this disorder.