A gas turbine comprising: a rotating member rotatable about a rotational axis and comprising a rotor; a shaft directional passage which is formed such that a central axis of the shaft directional passage is the same as a central axis of the rotor, and which is arranged such that cooling air can flow along a direction of the central axis of the rotor; a plurality of radial directional passages (63,65) provided in a circumferential direction of the rotating member and arranged such that the cooling air is compressed, in operation, by being provided outwardly from the central axis of the rotor, wherein one end of each of the radial directional passages (63,65) is communicated with the shaft directional passage and the other end is communicated with a cooling passage of a blade in a posterior area in an exterior of the rotating member; and an external passage including an air amount regulating unit, wherein one end thereof is communicated with an air supply for taking air in and the other end is communicated with the radial directional passages (63,65) from an end of the rotor to introduce the cooling air, and characterized in that the radial directional passages (63,65) comprise first radial directional passages formed as holes provided radially outwardly from the central axis of the shaft directional passage, second radial directional passages communicated to the cooling passages of the blades, and a cavity disposed between the first radial directional passages and the second radial direction passages, one end of which is communicated to a downstream end of the first radial directional passages and the other end is communicated to an upstream end of the second radial directional passages, wherein the first radial directional passages and the second radial directional passages are offset from each other with respect to an axial direction of the rotating member. a rotating member rotatable about a rotational axis and comprising a rotor; a shaft directional passage which is formed such that a central axis of the shaft directional passage is the same as a central axis of the rotor, and which is arranged such that cooling air can flow along a direction of the central axis of the rotor; a plurality of radial directional passages (63,65) provided in a circumferential direction of the rotating member and arranged such that the cooling air is compressed, in operation, by being provided outwardly from the central axis of the rotor, wherein one end of each of the radial directional passages (63,65) is communicated with the shaft directional passage and the other end is communicated with a cooling passage of a blade in a posterior area in an exterior of the rotating member; and an external passage including an air amount regulating unit, wherein one end thereof is communicated with an air supply for taking air in and the other end is communicated with the radial directional passages (63,65) from an end of the rotor to introduce the cooling air, and characterized in that the radial directional passages (63,65) comprise first radial directional passages formed as holes provided radially outwardly from the central axis of the shaft directional passage, second radial directional passages communicated to the cooling passages of the blades, and a cavity disposed between the first radial directional passages and the second radial direction passages, one end of which is communicated to a downstream end of the first radial directional passages and the other end is communicated to an upstream end of the second radial directional passages, wherein the first radial directional passages and the second radial directional passages are offset from each other with respect to an axial direction of the rotating member. second radial directional passages communicated to the cooling passages of the blades, and a cavity disposed between the first radial directional passages and the second radial direction passages, one end of which is communicated to a downstream end of the first radial directional passages and the other end is communicated to an upstream end of the second radial directional passages, wherein the first radial directional passages and the second radial directional passages are offset from each other with respect to an axial direction of the rotating member.