PURPOSE: To easily adjust the height of a clamping means by allowing the heights of all drive shafts to be changed at once by a drive shaft elevating mechanism when the height of a container is changed.

CONSTITUTION: A drive shaft 17 is rotated by means of cam mechanisms 34, 40 when the height of a container 2 is changed, and then the container 2 on a bin table 5 is gripped by both clamping arms 8A, B. As the bin table 5 is elevated, both clamping arms 8A, B and rotary shafts 18A, B are elevated together with the container 2. The rotary shafts 18A, B are isolated from the upper end of the drive shaft 17 and a pair of engagement portions 27, 28 to transmit the rotation of the drive shaft 17 to the rotary shafts 18A, B are also mutually isolated up and down. At this time, the condition that the container 2 is gripped by the clamping arms 8A, B is maintained by a spring 25. Then, a screw shaft 44 is driven by a drive shaft elevating mechanism 43 and the rotary shafts 18A, B are separated from the drive shaft 17 up and down by the elevation of an annular member 38, so that the heights of all clamping arms 8A, B can changed at once.