PURPOSE: To provide a high-temp. resisting secondary seal made of non- elastomer material for use in a gas turbine by installing a high-temp. carbon graphite secondary seal ring of split type which is to be biased in the axial direction by a first biasing means and in the radial direction by a second biasing means.

CONSTITUTION: A holding device is formed from a primary ring 30, holder 40, secondary seal rings 60 and 70, and a biasing means consisting of a disc 54 and spring 52, and the secondary seal rings 60 and 70 and the primary ring 30 are biased by the spring 52 via the disc 54 in the axial direction and the seal face 32 of the primary ring 30 is biased toward the surface 12 of a fit ring 10. The holder 40 has a contour portion 42 on that side of the holding device facing the periphery of the primary ring 30, and circular springs 62 and 82 are installed in the connection part 46 of the holder, so that the secondary seal rings 60 and 70 are biased in the radial direction. The whole surfaces of the secondary seal rings 60 and 70 are coated with a dry lubricant.