PURPOSE: To surely prevent collision while plural ceiling traveling cranes are operated at the same time.

CONSTITUTION: In a warehouse 3, automatically operated ceiling traveling cranes 1, 2 can be operated at the same time. Coordinates for showing the moving origin B of a metal band coil to be carried and the moving destination C thereof are given from a computer for managing the warehouse 3 to the respective ceiling traveling cranes 1, 2. The management computer gives an instruction for movement from the current position A to the moving origin B to the ceiling traveling crane 1, and sets a barrier 10 in a position apart from the position A by an interference preventing distance La. When the ceiling traveling crane 1 is moved to its moving origin B, a barrier 11 is set, and when the metal band coil is carried to the moving destination C, a barrier 12 is set. The management computer gives no moving command for going over the barriers 11, 12 set at that time to the other ceiling traveling crane 2.