An 85-year-old male patient with a history of asthma and hypertension was admitted to our hospital because of a fever of unknown origin. He complained of fever, fatigue, and weakness of lower extremities, which was considered due to infection, and he was administered antibiotics. Although his fever improved, there was little improvement in his condition or laboratory data. Enhanced-contrast computed tomography showed irregular hypertrophy of the aorta with contrast effect in the outer aortic wall and pulmonary embolism. He was diagnosed with Takayasu arteritis and pulmonary embolism. His clinical condition and aortic wall enhancement improved following steroid and anticoagulant drug therapy.