Microcopic polyangiitis (MPA) is a systemic disorder affecting small vessels. In MPA, the central nervous system involvements have rarely been reported. We experienced a case of MPA with subdural effusion and pachymeningitis in a 50-year-old woman. The diagnosis of MPA was made by the presence of mononeuritis multiplex, hematuria, pachymeningitis, and p-ANCA seropositivity in this patient. Subdural effusion was of exudates and an active suppurative inflammation was observed on the dural biopsy.