A case of intracranial mycotic aneurysm was reported, in whom repeated cerebral angiographies demonstrated the seccessive appearance of multiple aneurysms in a short term after the septic cerebral infection, and the importance of repeated angiography in the treatment of the intracranial mycotic aneurysm was stressed. A 44-year old male who had heart failure developed suddenly a left hemiparesis with irritable meningial signs on Nov. 3, 1973. The right carotid angiography carried out on Nov. 16 in an admitted hospital showed partial obliteration of cortical branches of the middle cerebral shift of the anterior cerebral artery due to the cerebral infarction. No aneurysm was demonstrated in the angiogram. The second angiography of the right carotid and vertebral artery was done on the admission of Dec. 18. The previously shown contralateral shift of the anterior cerebral artery was remarkably decreased, and an aneurysm of 3 mm in diameter was recognized at the cortical branch of the right middle cerebral artery on the parietal region. Any aneurysm was not revealed by the vertebral angiography. The third angiography of bilateral carotid and vertebral artery was performed on Dec. 25. The previously revealed aneurysm increased in size. Multiple aneurysms was demonstrated at the anterior branches of the insular artery. The vertebral angiography demonstrated multiple aneurysms at the peripheral portion of the bilateral posterior cerebral arteries. The patient was improved neurologically after the administration of antibiotics, and was discharged on Dec. 27 on the convenience of his family and would be followed in conservative cares.