A plurality of workpieces on which components are to be placed are lined up in a row and held by a workpiece holding body, and the workpiece holding body is placed on a carrier and is transported to a working position using a transport conveyor. After the workpiece holding body is chucked by a chuck portion, the workpiece holding body is separated from the carrier by linking an operation of lifting and lowering the chuck portion using a lifting-lowering mechanism and an operation of moving the carrier in a transport direction. The chuck portion which chucks the workpiece holding body is rotated by a rotation mechanism, postures of the plurality of workpieces which are held in the workpiece holding body are adjusted, and then, the components are placed on component placing parts using a placing head.