A 67-year-old man presented to our hospital with fever of 3 weeks’ duration. Chest computed tomography (CT) showed marked infiltrates in the right upper lobe and mild emphysema. Since he did not respond to antibiotic therapy, we performed a bronchoscopy. Aspergillus niger was detected in bronchial lavage fluid culture obtained from the right upper lobe. He was diagnosed with chronic progressive pulmonary aspergillosis due to Aspergillus niger. Voriconazole, liposomal amphotericin B (L-AMB), and their combination with caspofungin (CPFG) had no effect. Identification of bacterial species and a drug susceptibility test were reperformed, which identified Aspergillus tubingensis. Based on the results of the drug susceptibility test, L-AMB, CPFG, and flucytosine (5-FC) combination therapy was started. Three months later, his symptoms had improved, and a small improvement was observed on CT when compared to the findings on admission. Drug susceptibility tests are a useful tool in the treatment of pulmonary aspergillosis, which is difficult to treat.