A 54-year-old man presented with a rare case of cavernous angioma located in the ventral vermis manifesting as sudden onset of vertigo, followed by cerebellar ataxia. T(1)-weighted magnetic resonance imaging revealed a 1.5-cm homogeneously enhanced lesion in the ventral vermis. The postpyramidal fissure was opened widely, and upward exploration through the incision enabled piecemeal removal of the lesion without deterioration of the symptoms. The histological diagnosis was cavernous hemangioma with ruptured enlarged varices. The trans-postpyramidal fissure approach allows visualization of the entire fourth ventricle and avoids damaging the cerebellar nuclei and major postoperative cerebellar dysfunction.