Transthoracic ultrasonography suprasternal long axis view is a powerful tool for evaluating aortic arch lesions. It can be performed with ultrasound equipment in many facilities and can be repeated quickly at bedside or outpatients, without anesthesia and painless. It can also depict the aortic arch well. Transesophageal echocardiography (TEE) is highly necessary in patients with suspected aortogenic embolism, but there are some patients who cannot perform it. Transthoracic ultrasonography suprasternal long axis view can supplement some of the role of TEE. We could really evaluate a mobile aortic atheromatous plaque in a stroke patient who had right aortic arch using by this technique. Evaluation of aortic arch by transthoracic ultrasonography suprasternal long axis view is useful in embolic source search of cerebral embolism patients.