A compressor for use in a gas turbine engine, comprising: a cylindrical casing having a longitudinal axis and an inner circumferential surface about the longitudinal axis; a plurality of rotor blade wheels mounted within the casing for rotation about the longitudinal axis, each of the rotor blade wheels having a number of rotor blades positioned at intervals in a circumferential direction about the longitudinal axis; a plurality of stator blade wheels unrotatably mounted within the casing, each of the stator blade wheels having a number of stator blades positioned at intervals in the circumferential direction about the longitudinal axis, the stator blades each having a flange defined therewith at radially outward ends thereof by which the stator blades are supported on the inner circumferential surface of the casing, the rotor and stator blade wheels being positioned alternately in an axial direction parallel to the longitudinal axis; seal rings positioned on the inner circumferential surface of the casing to oppose radially outward ends of the rotor blades; the casing having a plurality pairs of circumferentially extending engagement grooves defined in the inner circumferential surface thereof and the seal rings each having a pair of complementary circumferentially extending engagement projections, so that the seal rings are supported on the inner circumferential surface of the casing by engaging each pair of engagement projections with the associated each pair of engagement grooves, the flanges of the stator blades and the seal rings being shaped and sized so that neighborhood flanges of a neighborhood stator blade and the seal ring in the axial direction are substantially in contact with each other in the axial direction and the flanges of the stator blades and the seal rings are supported on the inner circumferential surface of the casing, a length of the seal ring in the axial direction in one rotor blade wheel being different from that in another rotor blade wheel, characterized in that the compressor further comprises a leaf spring provided between the outer flange of each respective stator blade and an opposing groove defined in the inner circumferential surface of the outer casing to thereby force the stator blades radially inwardly so that the stator blades are supported in a stable manner, wherein each of the leaf springs is positioned in the form of an arch when viewed in the axial direction so that opposite ends of the leaf spring are supported by the casing and a central portion of the leaf spring is forced on an outer periphery of the stator blade. a cylindrical casing having a longitudinal axis and an inner circumferential surface about the longitudinal axis; a plurality of rotor blade wheels mounted within the casing for rotation about the longitudinal axis, each of the rotor blade wheels having a number of rotor blades positioned at intervals in a circumferential direction about the longitudinal axis; a plurality of stator blade wheels unrotatably mounted within the casing, each of the stator blade wheels having a number of stator blades positioned at intervals in the circumferential direction about the longitudinal axis, the stator blades each having a flange defined therewith at radially outward ends thereof by which the stator blades are supported on the inner circumferential surface of the casing, the rotor and stator blade wheels being positioned alternately in an axial direction parallel to the longitudinal axis; seal rings positioned on the inner circumferential surface of the casing to oppose radially outward ends of the rotor blades; the casing having a plurality pairs of circumferentially extending engagement grooves defined in the inner circumferential surface thereof and the seal rings each having a pair of complementary circumferentially extending engagement projections, so that the seal rings are supported on the inner circumferential surface of the casing by engaging each pair of engagement projections with the associated each pair of engagement grooves, the flanges of the stator blades and the seal rings being shaped and sized so that neighborhood flanges of a neighborhood stator blade and the seal ring in the axial direction are substantially in contact with each other in the axial direction and the flanges of the stator blades and the seal rings are supported on the inner circumferential surface of the casing, a length of the seal ring in the axial direction in one rotor blade wheel being different from that in another rotor blade wheel, characterized in that the compressor further comprises a leaf spring provided between the outer flange of each respective stator blade and an opposing groove defined in the inner circumferential surface of the outer casing to thereby force the stator blades radially inwardly so that the stator blades are supported in a stable manner, wherein each of the leaf springs is positioned in the form of an arch when viewed in the axial direction so that opposite ends of the leaf spring are supported by the casing and a central portion of the leaf spring is forced on an outer periphery of the stator blade.