We measured spontaneous photon emission and delayed luminescence from human cancerous lung tissue and compared with those from adjacent normal lung tissue. For the detection of extremely weak photon emission from tissue we used a sensitive photomultiplier tube attached to a dark chamber. The samples were illuminated with a metal halide lamp for measurement of delayed luminescence. Extracted samples from surgery were measured within an hour. We found that the delayed luminescence showed salient aspects in making discrimination between tumor and adjacent normal tissue. Squamous cell carcinoma had more prominent character in delayed luminescence than adenocarcinoma.