There is provided a system 10 including at least one of inspection machines 20 and 22 and an NG board discharge machine 24 which moves an NG board to a checking position visible to a worker. The system 10 acquires positional information of a circuit board during conveyance, and stores the NG board by associating a work result for the NG board with the positional information. In this manner, the positional information of the NG board is acquired. Based on the positional information, it is determined whether or not the circuit board conveyed to the NG board discharge machine is the NG board. When the circuit board conveyed to the NG board discharge machine is the NG board, a checking-purpose working machine discharges the NG board to the checking position. In this manner, it is not necessary to arrange the checking-purpose working machine adjacent of a downstream side of the inspection machines, and it is possible to arrange another working machine between the checking-purpose working machine and the inspection machine. In addition, even when the multiple inspection machines are arranged in the system, one checking-purpose working machine can correspond to the multiple inspection machines.