A case of bronchogenic in situ carcinoma originating in forth order bronchi was reported. Sputum cytology showed class IV in lung cancer mass screening in a 69-year-old male, although X-ray was negative. Bronchofiber scopy was repeated twice, and fine granular change of spur between Blai and ii was found in the second time. Right upper lobectomy was underwent, and post-surgical histology was in situ squamous cell carcinoma. The literature on early lung cancer was reviewed, and implication for management of bronchofiberscopic early lung cancer in general rule for clinical and pathological record of lung cancer was discussed.