PURPOSE: To provide a thermal seal having effective heat transmission resistance, enabling the use of a member piece for optimizing a hermetical sealing effect and facilitating the removable of the member piece, regarding a thermal seal for substantially preventing the clashing of high-temperature gas with the outer peripheral surface of the rotor spacer disk of a gas turbine engine.

CONSTITUTION: A hermetical sealing member piece 46 is attached to the full periphery of rotor spacer disks 30 and 32. To this end, a conventional annular groove formed (as a part of a high/low surface shape for hermetical sealing) in the outer peripheral surface of each spacer disk is improved to be a dovetail groove designed to receive the complimentary or mating portion of the hermetical sealing member piece. In other words, a plurality of hermetical sealing member pieces are mated with each of annular grooves adjacent to each other.