Alveolar echinococcosis results from infection by E. multilocularis and has spread throughout Japan's northern island of Hokkaido during the last four decades. However, this malignant parasitic disease is very rare on the main island of Honshu. Here we report a case of alveolar echinococcosis of the lung, probably the first case found in Aichi Prefecture. The patient, a 65-year-old male, was admitted on March 1989 with marked Rt. hypochondralgia. Though Rt. pleural fluid was observed on chest radiograms, he showed moderate improvement after the chemotherapy for tuberculosis. On March 1993, he was admitted again as x-rays revealed marked multiple nodular shadows on the lungs. Open lung biopsy was follewed. The result of pathological diagnosis was parasitosis of the lung, but no parasite was identified. Although symptomatic therapy was continued for one year and six months, his symptom became worse and he was readmitted. Further history taking revealed the fact that he had resided on one of Chi-shima islands off Hokkaido for one year. A positive result of ELISA was confirmed. Long-term Albendazole therapy can result in a parasitological cure with reduction of the lesion in the lung.