To resolve a problem that, when sand, a fertilizer or the like is filled into a large bag by one worker, an opening of a bag is not opened uniformly and a content is spilled out of the bag, and additionally the bag cannot be fixed and filling work must be carried out by one hand.

A bag can be easily fixed by the equal expansion of an opening of the bag through several claws by an operation of a handle or a foot pedal and by no-fixing of the bag with clips and the like, the bag can be fixed only by the hooking of the end of the bag opening with the claws, so that when the claws are opened, a gear rotates to enable the bag to be equally expanded and if the bag is fixed to a folding stand, both hands of a worker can freely move.