Anterior spinal artery (ASA) aneurysms are rare, and the majority are associated with vascular lesions such as arteriovenous malformations, moyamoya disease, and aortic stenosis. Herein, we report a case of a ruptured anterior spinal artery aneurysm caused by bilateral vertebral artery (VA) occlusion, which was treated by coil embolization. An 83-year-old man was found collapsed at home, and was brought in by emergency. His consciousness level was I-1 on the Japan Coma Scale, and there were no symptoms such as paralysis in the extremities. Computed tomography showed Fisher 3 subarachnoid hemorrhage, while magnetic resonance angiography showed an aneurysm in the right VA. Digital subtraction angiography showed bilateral VA occlusion, and an aneurysm was found on the dilated ASA as a collateral circulation. Coil embolization was performed after confirmation of no hemodynamic problems. No postoperative adverse events were observed. Coil embolization may be an effective treatment for ruptured aneurysms of the ASA.