Jaw claudication is a common symptom of giant cell arteritis (GCA), although atherothrombotic external carotid artery (ECA) occlusion is also known to cause jaw claudication. The patient was a 75-year-old male who experienced severe right jaw pain while chewing solid food. Magnetic resonance (MR) angiography showed right ECA occlusion. Based on laboratory tests and contrast-enhanced computed tomography (CT) angiography, atherothrombosis, not GCA, was suspected to be the cause of jaw claudication. Following conservative therapy with cilostazol, the pain was gradually alleviated in two months, and subsequent MR angiography after four months showed blood flow in the stenosed right ECA. The symptom completely disappeared in six months. Based on a previous report, we expected that jaw claudication will be ameliorated due to the development of collateral supply; however, spontaneous ECA recanalization caused improvement of symptoms in this case.