PURPOSE: To perform easy and rapid dumping of contents in a container by arranging a container support member facing a pair of arms located to a body hung down by means of a crane, and providing a drive means to hold the container by rotating the support member and rotate the container.

CONSTITUTION: When through drive of a cylinder located in a body 1, two slide levers 2 are moved in a direction in which the slide levers are retracted in a body 1, an engaging member 8 is inserted in a hole to engage them with each other, and a container 15 is supported in a fixed state to a dumping device. The dumping device to which the container 15 is supported is lifted down by means of a crane to lift the container 15, which is moved on a load-carrying platform T of a truck. When, through drive of a cylinder 12 in an arm 6, a support member 7 is rotated, the container 15 is rotated to dump iron scraps in the container 15 on a load-carrying platform T. Through re-drive of the cylinder 12 in the arm 6, the support member is rotated until the opening of the container 15 is brought into an up state, and the container 15 is moved to a given position with the aid of the crane.