An object of the present invention is to provide a ring segment of a gas
turbine in which the temperature is maintained low, damage due to high temperature oxidation is prevented, and high temperature deformation is prevented. In order to achieve the object, the present invention provides a ring segment of a gas
turbine which comprises a blade ring, a main shaft and moving blades comprising a plurality of individual units which define an annular form by being arranged around the
peripheral direction of the main shaft, and disposed so that its inner
peripheral surface is maintained at a constant distance from the tips of the moving blades, wherein grooves which extend along the axial direction of the main shaft of the
turbine are formed upon of the individual units so as mutually to confront one another; a seal plate which is inserted into each mutually confronting pair of the grooves so as to connect together the adjacent pair of individual units; and contact surfaces which are formed at positions more radially inward than the seal plates, which extend in the axial direction and the
peripheral direction and which mutually contact one another.