Since carbon beam therapy for non-small cell lung cancer (NSCLC) was initiated in October 1996, seven trials have been conducted; three have already closed and the remaining four are ongoing. The local control rate, cause-specific survival rate, and overall survival rate of 141 patients with clinical stage I NSCLC were 82%, 58%, and 42%, respectively. Radiation pneumonia was rare (2.1%) and not serious. In the phase II clinical study, the local control rate achieved in 50 patients was 100%, with no radiation pneumonia, resulting in a 60% overall survival rate. Carbon beam therapy could be an alternative to surgery, especially for lung cancer patients of advanced age and/or with complications. For locally advanced lung cancer treated with carbon beam therapy, excellent local control comparable to that in stage INSCLC has been demonstrated and offers hopeful prospects for the treatment of lung cancer.