Spinal arteriovenous fistula is extremely rare in children. Weakness and sensory disturbance in the lower extremities are the specific clinical presentations. Children, however, commonly have no subjective symptoms; in rare cases, a continuous murmur is the only physical finding. An 18-month-old boy was referred for evaluation of a continuous murmur audible at the back. He had no motor or sensory disorder; only a Levine 3/6 continuous murmur audible at the back was found. Echocardiography showed a structurally normal heart but indicated ascending continuous blood flow behind the aortic arch and dilatation of the innominate vein. We suspected spinal arteriovenous fistula, and it was visualized on computed tomography angiography. Spinal arteriovenous fistula was detected using only auscultation and echocardiography. Suspicion of this anomaly on careful auscultation and simple examination, and confirmation on detailed examination, even in the absence of motor or sensory disturbance, is important.