Seal apparatus of turbine and thermal power system

A sealing device for a turbine has a sealing member provided in a gap between a rotor and a stator arranged to surround the rotor, and a fluid path provided within the stator, to introduce, into the stator, a cooling medium used to cool stationary blades extending radially inward from the stator, and to flow the cooling medium at least to an upstream side of the sealing member.