PURPOSE: To quicken detection of positional malfunction and prevent a band from being damaged by a method wherein a positioning pusher is equipped with a plurality of work positioning state detecting mechanisms, and a carrier robot is controlled based on comparison between detection information and instruction array pattern information.

CONSTITUTION: Mechanisms 14 to 17 for detecting whether or not a work 1 is correctly engaged with a positioning stopper 8 at the time of centering are provided on a positioning board 10c of a pusher 10. That is, when the work 1 is properly positioned, the detecting mechanisms 14, 16 operate to output detection signal. When positioning is not proper, the detecting mechanisms 14, 17 or 13, 16 operate to output signal. A carrier robot 11 compares this signal with array pattern instruction signal to determine positioning status so that holding and carrying is performed when the positioning is proper, and if not, operation is urgently stopped. This constitution can prevent a hand from being damaged.