A 62-year-old man with high fever and in a state of disorientation was transferred to our hospital. One year before this transfer, he had undergone total arch replacement surgery for thoracic aortic dissection. On admission to our hospital, head MRI revealed multiple brain abscesses in the territory of the vertebral-basilar artery, and chest CT showed gas around the aortic graft, in particular, at the origin of the left subclavian artery. We diagnosed him with brain abscesses in the left vertebral-basilar artery resulting from an infected aortic graft. We immediately began administration of intravenous antibiotics. Although his blood, urine, and cerebrospinal fluid cultures were negative, fortunately, the brain abscesses and ectopic gas disappeared. Since reports of only antibiotic use for treating brain abscesses due to aortic graft infection are rare, the appropriate duration of antibiotic administration has not been established yet. Therefore, careful observation is required in this case.