Disclosed is a rotary anode type X-ray comprising a substantially columnar stator, a cylindrical first rotor coupled around the stator, at least one hydrodynamic slide bearing region including a spiral groove, and arranged in the coupled portion between the stator and the first rotor, and a cylindrical second rotor arranged coaxial with and outside the first rotor with a gap for the heat insulation and bonded directly or indirectly to a anode disk, the second rotor being bonded to the first rotor in an open edge region positioned remote from the anode disk in terms of the heat transmission route, wherein a plurality of slits extending substantially along the axis of rotation are formed apart from each other in the circumferential direction in the open edge region in which the second rotor is bonded to the first rotor.