Seal structure, turbine machine having the same, and power generating plant equipped with the same

A seal structure comprising:

• shrouds that are provided at tips of a plurality of blades on which a main flow of fluid impinges and that come into contact with adjacent shrouds to form a cylindrical shape;
• a sealing part connected to a structure body facing the shrouds;
• and
• a space that is defined by downstream sides of the shrouds, a downstream side of the sealing part, and a wall on a downstream side of the structure body and that communicates with the main flow of fluid that has impinged on the blades,
• wherein an end of the wall on the downstream side of the structure body is formed so as to be disposed a predetermined distance away from a shroud extension extending toward the downstream side of the shrouds and away from a sealing-part extension provided substantially parallel to the shroud extension and extending toward the downstream side of the sealing part and so as to be located on an opposite side of the shroud extension with respect to the sealing part extension.