The most important issues in the segmentectomy for lung cancer, are the accurate establishment of the suture line and to reduce local recurrence at the resection margin. There are two methods:bronchial dominance as an indicator and intravenous indocyanine green (ICG) as an indicator of blood flow dominance. We have been performing identification by ICG since 2020. After the pulmonary arteriovenous and bronchus are resected, ICG is injected intravenously, and the borders between fluorescent and non-fluorescent area is identified using a ICG thoracoscope, and are resected using an electro-surgical unit or stapler. After that, additional ICG is administered, pulmonary blood flow is checked, and if an uncontaminated area is identified, an additional resection is performed. We have retrospectively reviewed 16 cases of ICG method for lung cancer( all at clinical stageⅠ) performed since January 2020, and no recurrence has been observed. We present the details of these cases and report the usefulness of the ICG fluorescence system.