An abnormal shadow was observed on the chest radiograph of a 39-year-old man during health examination. The chest CT scan showed a consolidation around the cysts in the left upper lobe. The patient was diagnosed with Mycobacterium xenopi lung infection based on the presence of acid-fast bacilli in the sputum culture several times, which were identified as Mycobacterium xenopi by DNA-DNA hybridization. Two weeks after the initation of chemotherapy with 4 drugs (isoniazid, rifampicin, ethambutol, and clarithromycin), the patient's sputum smear and culture test results were negative; additionally, the consolidation on the chest CT scan improved after 10 months of treatment. There have been several case reports on Mycobacterium xenopi lung infection in Japan. However, few have studied Mycobacterium xenopi lung infections associated with multiple lung cysts that responded well to chemotherapy are rare.