A 68-year-old man, complaining of fever and puriform sputum, was referred to our hospital. A giant abscess was detected in the upper lobe of the right lung. Percutaneous drainage of a lung abscess was carried out. When the pus collected was cultured, Candida was 1+ and Escherichia coli was 2+. Later, it became difficult to control the abscess by drainage, and cavernostomy was selected. The contents of the abscess cavity were removed, and the cavity was opened, followed by exchange of gauze every day. For 14 months after cavernostomy, once-weekly gauze exchange was continued at the outpatient clinic to clean the abscess cavity. Finally, the abscess was filled with a free greater omentum flap, accompanied by microvascular anastomosis. In this way, the intractable lung abscess was successfully cured. Conventionally, surgical treatment, particularly cavernostomy, has been applied only to limited cases when dealing with a lung abscess. Our experience with the present case suggests that surgical treatment, including cavernostomy as one option, should also be considered when dealing with lung abscesses resisting medical treatment and causing compromised respiratory function. To enable maximum utilization of the greater omental flap, which is available in only a limited amount, it seems useful to prepare and graft a free omental flap making use of microvascular surgery.