To execute the accurate and reliable binding by preventing any positional deviation of an object to be bound by holding means having a simple mechanism and a simple structure, and accurately and reliably holding the object at the predetermined position.

A holding mechanism includes an upper holder for pressing and holding a large bundle A on a loading stand from above, a front holder having a front holding member 182 for holding and fixing the front side of the large bundle A by the turn of a front holder base part 183, a side holder 19 which is turnably supported by the front holding member 182 of the front holder to hold, and fix right and left sides on the front side of the large bundle A by the urging force of a spring member, and a rear holder 20 for holding the rear part of the large bundle A.