To thoroughly prevent dust from scattering.

This bulk material loading device carries and supplies bulk materials of cargo to a boom conveyor 7 of a loading machine 2 installed on the ground for travelling by a tripper 5, whose approximately whole is covered with a seal belt 26 from above. Since the seal belt 26 is deformed according to the movement of an inclined part 17 of the tripper 5 to block the upper part, covering can be always performed in a joint part 22. Since the loading machine 2 and the tripper 5 are moved under the seal belt 26, the whole conveying passage for the cargo can be always covered with the seal belt 26.