A rotating anode type X-ray tube , comprising: a fixed shaft having a first surface (FA) intersecting a direction parallel to a rotation axis (A1); a rotor supported by dynamic pressure bearings including a lubricant (M) put into a gap between the fixed shaft and the rotor to rotate about the rotation axis (A1) around the fixed shaft ; a cathode arranged to emit electrons; and an anode target provided at the rotor and arranged to generate X-rays by electrons emitted from the cathode colliding with the anode target , wherein the rotor comprises: a first cylinder having a second surface (FB) intersecting a direction parallel to the rotation axis (A1); a second cylinder being in contact with the second surface (FB) and facing the first surface (FA) via the lubricant (M); and a third cylinder located on a side opposite to the first and second surfaces (FA,FB) with the second cylinder sandwiched between the third cylinder and the first and second surfaces (FA,FB), wherein a first threaded portion (S1) provided on an inner surface of the first cylinder and a second threaded portion (S2) provided on an outer peripheral surface of the third cylinder are tightened, and wherein a screw member (S4) is screwed in a third threaded portion (S3) provided on an inner peripheral surface of a hole which penetrates the third cylinder in the direction parallel to the rotation axis (A1), and a tip portion of the screw member (S4) presses the second cylinder against the second surface (FB). a fixed shaft having a first surface (FA) intersecting a direction parallel to a rotation axis (A1); a rotor supported by dynamic pressure bearings including a lubricant (M) put into a gap between the fixed shaft and the rotor to rotate about the rotation axis (A1) around the fixed shaft ; a cathode arranged to emit electrons; and an anode target provided at the rotor and arranged to generate X-rays by electrons emitted from the cathode colliding with the anode target , wherein the rotor comprises: a first cylinder having a second surface (FB) intersecting a direction parallel to the rotation axis (A1); a second cylinder being in contact with the second surface (FB) and facing the first surface (FA) via the lubricant (M); and a third cylinder located on a side opposite to the first and second surfaces (FA,FB) with the second cylinder sandwiched between the third cylinder and the first and second surfaces (FA,FB), a first cylinder having a second surface (FB) intersecting a direction parallel to the rotation axis (A1); a second cylinder being in contact with the second surface (FB) and facing the first surface (FA) via the lubricant (M); and a third cylinder located on a side opposite to the first and second surfaces (FA,FB) with the second cylinder sandwiched between the third cylinder and the first and second surfaces (FA,FB), wherein a first threaded portion (S1) provided on an inner surface of the first cylinder and a second threaded portion (S2) provided on an outer peripheral surface of the third cylinder are tightened, and wherein a screw member (S4) is screwed in a third threaded portion (S3) provided on an inner peripheral surface of a hole which penetrates the third cylinder in the direction parallel to the rotation axis (A1), and a tip portion of the screw member (S4) presses the second cylinder against the second surface (FB). <EOS>