UNIT SUPPORT LEG AND SUPPORT BOLT USED FOR THE SAME

PROBLEM TO BE SOLVED: To construct double floors capable of being manufactured with excellent productivity at low cost, having sufficient strength in spite of long length and having superior sound-insulating and vibration-damping effects and high floor height with surpassing workability. SOLUTION: The unit support leg is constituted so that a support plate 30 is installed in a freely height adjustable manner through a nut 20 screwed to the upper section of the support bolt 10 rotatably disposed in upright on a floor-contacting base 1 and used for adjusting a level. The support bolt 10 consists of a hollow cylindrical body, in which a collar section 11 expanded to the side is formed at a lower end section, which is draw-formed so as to be transferred from a large diametral section 12 in a lower section to a small diametral section 14 in an upper section through a gentle inclined section 13 and in which a screw section 15 is formed to the outer circumferential surface of at least the upper section of the small diamteral section 14 while an engaging section 16 for a rotary tool is formed at a top end section, at that time. The floor-contacting base 1 has a through-hole 4 in the vertical direction, and a recessed section 5 receiving the collar section of the support bolt 10 is formed around the through-hole 4 so as to be upwards opened.