To provide a level adjusting tool capable of easily adjusting a level of a container to a level of a working platform without separately requiring motive power.

This level adjusting tool is composed of a rotary column 11a detachably installed on a corner metallic material 35a of the container 34 and a support base 48 installed in the corner between a floor surface 29 and a side wall 47 of a platform 45. In use, the rotary column 11a is lifted in a state of being installed on the corner metallic material 35a, and the lower end of its semicircular bar body 27 is arranged between a stopper 49a and a stopper 49b fixed on the support base 48. When a trailer is further retreated in this state, the rotary column 11a rotates in the clockwise direction with the lower end of the semicircular bar body 27 as a fulcrum as indicated in its (2). A position of the corner metallic material 35a engaging with the rotary column 11a via a pin 17 rises thereby, and the container 34 is lifted.