PURPOSE: To prevent feed water from steaming by using an exhaust gas cooler of a gas turbine as a reheater or a part of the reheater for a boiler.

CONSTITUTION: In an exhaust gas recombustion combined cycle plant, a feed water pipeline 14 communicated with a gas feed water heater 13 is directly connected with a heater side flow passage 6 of a boiler 1. A steam return pipe 15 communicated with a high pressure steam turbine 5 or a middle pressure steam turbine not illustrated is connected with a reheated steam supply pipeline 23 which is designed to run through a gas turbine exhaust cooler 12 and is communicated with a reheater side flow passage 6 of the boiler. Therefore, the gas turbine exhaust cooler 12 is capable of functioning as a part of a reheater 7.