Vascular ring is a congenital anomaly of the aorta and its branches that compresses the trachea and/or esophagus. Infants with vascular ring may have critical dyspnea due to airway obstruction, which is called a dying spell. In addition, vascular ring leads to secondary malacia of the trachea and bronchus. To prevent dying spells and progression of malacia, vascular ring should be diagnosed as soon as possible. We report here a case of a 5-month-old girl with vascular ring affecting the right aortic arch, aortic diverticulum, and ligamentum arteriosum. She had stridor from birth and afebrile convulsions due to dying spells at 5 months of age. Transthoracic echocardiography revealed right aortic arch, and plain computed tomography (CT) revealed severe tracheal stenosis. Finally, we diagnosed vascular ring based on contrast-enhanced CT imaging. We should consider vascular ring when we encounter infants with stridor. Echocardiography is helpful for examining the structure of aorta, and if an aortic anomaly is noted, contrast-enhanced CT should be performed to diagnose vascular ring immediately.