We report an extremely rare case of multiple saccular aneurysms of the extracranial and intracranial internal carotid artery associated with convexobasia of the left temporal region and arachnoid cyst in a 6-year-old boy. A 6-year-old male patient was admitted to the hospital with chief complaint of ptosis and engorgement of the left eyelid for 50 days. A 4 x 10-cm bony protuberance of the left temporal region with hemangiectasia was observed to beat with pulse without vascular murmur. computed tomographic angiography (CTA) showed two saccular aneurysms of the left internal carotid artery. The first one which was about 3 cm in length and 2 cm in maximum diameter was located in the middle of the petrous portion (including parts of C2 and C3). The second one which was about the same size was located from the middle of the cavernous portion to the upper end of the left internal carotid artery. Computed tomography showed an arachnoid cyst in the left temporal region and abnormality of the left temporal bone. According to the specific circumstances of this patient, we believe that surgical treatment is rather risky and the loss might outweigh the gain. Therefore, we suggested to the parents that the child should be followed up for the coming years for monitoring and possible treatment. Multiple saccular aneurysms of extracranial and intracranial internal carotid artery in children are extremely rare. According to this case, the child had congenital bony protuberance of the left temporal region with hemangiectasia, which made this case particularly specific. Besides all those discovered abnormalities, this child was a healthy boy. Due to the difficulty and high risk of possible surgical treatment, we suggested that no further treatment be performed at the moment and the child should be followed up for a long period of time. Worthy examinations such as CT, CTA, and MRI are recommended for reviewing the development of aneurysms and CNS of this boy. Further treatment might be performed in the future. We welcome all forms of discussion about this case and similar cases around the globe.