PURPOSE: To obtain a small size, light weight system enable of quick assembling with low cost, by obliquely inserting a rotary support around a fulcrum through rotation of a lead screw.

CONSTITUTION: Upon driving of a motor 34, a lead screw 35 will rotate. Since second roller 51 arranged at the tip of a pin 48 formed integrally with a lead nut 36 will limit rotation of lead nut 36 through a guide rail 50, the lead nut 36 will never rotate but move in parallel as the rotation of the lead screw 35. Consequently the first roller 37 arranged in the center of a pin 48 formed integrally with the lead nut 36 will push a rotary support 41 in the axial direction of the lead screw 35 while being guided by an elongated hole 38. Since supported rotatably at the fulcrum section 39, the rotary support 41 will rotate around said section 39, to insert the X-ray tube 40 fixed above said support 41 obliquely.