Achieving local control of lung cancer by means of radiotherapy depends on a balance between the radiosensitivity of tumor tissue and the degree of damage of the normal tissue, especially in lung tissue. Recently, the physical innovation of radiotherapy makes it possible to irradiate higher doses to tumor tissue with lower exposure to normal tissue. Both image-guided radiotherapy, which is radiotherapy with a high degree of accuracy used with imaging modality, and several techniques of respiratory gating or interception for moving targets have been developed. Using these new techniques, stereotactic radiotherapy (SRT) is used to treat patients with peripheral early non-small-cell lung cancer. The phase II clinical trial of SRT for operable stage I non-small-cell lung cancer was safely carried out in Japan with promising survival rates. Carbon-ion therapy and proton therapy, using the same materials as SRT, are investigated.