A surgically confirmed primary leptomeningeal malignant melanoma (PLMM) discovered at the parietal region is reported in a 72-year-old male. He developed progressive right hemiparesis and speech disorders caused by a parietal large mass that simulated a growing meningioma. A well-defined, dark-black tumor was removed completely and was histopathologically diagnosed as a malignant melanoma. No melanomas were detected by systemic clinical and radiological examination, including dermatological and ophthalmologic examinations. Follow-up examination 18 months postoperatively showed no evidence of recurrence of the tumor. The patient gradually became bedridden probably because of decreased general activity possibly due to brain atrophy and died of cardiac failure without any evidence of recurrence. Because of the absence of other systemic localizations, we consider this melanoma as primary. A favorable outcome was obtained by surgical treatment alone.