Animal (mouse and guinea pig) pulmonary tuberculosis models were established, using an automated inhalation exposure apparatus (Glas-Col Corp., USA, Model 099CA-4212). This apparatus includes four steps--preheating, nebulization, cloud decay and decontamination. The optimal conditions for M. tuberculosis H37Rv strain infection experiments were as follows: 10(5-6) colony forming unit (cfu) tubercle bacilli; preheating for 15 min.; nebulization for 90 min.; cloud decay for 15 min. and decontamination for 5 min. When 10(4) cfu M. tuberculosis H37Rv strain were introduced into the lungs of interferon (IFN)-gamma knockout mice, using the inhalation exposure apparatus and were followed up for 9 months, the primitive cavitary lesions were observed. This apparatus was also useful for inhalation exposure experiments of guinea pigs. This apparatus can also be utilized for animal inhalation experiments of allergens.