The author examined the functional state of pancreas biochemically and morphologically in 37 normal rabbits under the invasion of pulmonary resection. Results obtained are as follows; (1) The blood diastase level is raised to the uppermost on the 3rd day after the pulmonary resection, and is restored to the preoperative level on the 14th to the 21 st day. The blood sugar level rised to reach the peak on the 1st day after the pulmonary resection and falls down to the normal on the 5th to the 10th day. Staub effect is negative postoperatively and becomes positive on the 5th to the Loth day. (2) As for the histological findings, the parenchymal cells show the atrophy on the 3rd to the 7 th after the pulmonary resection. There are no remarkable changes in the Islets of Langerhans. A slight increase of β-cells is noticed on the 3rd day. (3) From the above it is concluded that the pulmonary resection in the rabbits leads to the developement of slight disturbances of the external and internal secretary function of pancreas, but these troubleso recover after some day.