We have experienced a case of pulmonary adenocarcinoma looked like cavitary lesion of pulmonary tuberculosis in 49-year-old male patient. He has taken antituberculous medication for 5 months under the impression of pulmonary tuberculosis with cavity at local hospital. The cavitary lesion was changed nodular mass on follow-up chest X-ray. Transthoracic fine needle aspiration was done and cytologic specimen suggested squamous cell carcinoma. Right middle lobectomy was performed. The nodular mass, which was confirmed as adenocarcinoma on microscopic examination, had central cavity filled with hemorrhage.