In a component-mounted-board production line in which an automatic exchanging device moves along a row of multiple component mounters, each component mounter is provided with a power supplying section that supplies power wirelessly. The automatic exchanging device is provided with a power receiving section that receives electric power supplied wirelessly from the power supplying section of the component mounter that the automatic exchanging device is facing, a monitoring section that monitors whether a person or object has entered a monitoring area around the automatic exchanging device, and a safety circuit section that turns off the power supply to a motor that is the driving source of the automatic exchanging device but continues supplying power to the monitoring section and the like when the monitoring section detects that a person or object has entered the monitoring area.