PURPOSE: To ensure the easy adjustment of high precision and obtain stable support by lifting an upper body monolithically with a support ring nut for height adjustment against a lower body and fixing the upper body to the ring nut and then to the lower body.
CONSTITUTION: A support ring nut 38 is finely adjusted in rotational angle, thereby adjusting the height of an upper body 34 from a lower body 32 to high precision. Also, the support ring nut 38 is fixed to the lower body 32 via the effect of a tightening means such as a spring nut 37 and a set screw 45, and the upper body 34 is connected to the support ring nut 38. Then, the upper body 32 comes to be placed and fixed on the ring nut 38 of a relatively large external size through a relatively large contact area. Therefore, a foundation 3 and a structure thereon can be stably supported without any occurrence of a vibration due to the operation thereof and with an increase in resistance against the application of an external force.