To constitute a device in a simple structure, improve profitability and stability, and so carry out maintenance easily by feeding gland seal steam to an inside through a feed port after it is circulated once around a rotor in an annular passage from the feed port, in a gland main body installing part.

Gland seal steam is fed to a feed port 5, it is circulated once around a rotor passing the annular steam passage 15 formed on a gland main body installing part 10, and then it is led to the feed port 9 of gland seal steam. It is led from the feed port 9 to the annular flow-in passage of the gland main body, and it is supplied toward the outer peripheral surface of the rotor so as to obtain seal function. After that, it collects from the flow-out passage of the gland main body to a discharging port 6 together with air invaded from an outside, and it is discharged toward a gland condenser. Since high temperature gland seal steam is circulated once around the inner surface of the gland main body installing part 10 enclosing the rotor by a steam passage 10, the whole of he gland main body installing part 10 is heated uniformly so as to prevent generation of deviated heat deformation.