PURPOSE: To improve heat efficiency at the intermediate load time of a turbo- engine by installing an opening adjust member consisting of a thermosensitive deformation material.

CONSTITUTION: By installing a member 30 for automatically adjusting an opening consisting of a thermosensitive deformation material on the entrance opening 27 of a turbine cooling air guide duct 23, the opening becomes big and the flow rate of a compressed air 13 to the turbine cooling air guide duct 23 becomes much at the maximum load time of a turbo-engine and the opening becomes small and the flow rate of the compressed air 13 to the turbine cooling air guide duct 23 is squeezed at the intermediate load time.