After a chuck portion chucks a workpiece holding body which aligns and holds a plurality of workpieces on which components are to be placed, the posture of the workpieces held in the workpiece holding body is adjusted due to rotation mechanism by rotating the chuck portion around an axial line which extends in an aligning direction of the plurality of workpieces held in the workpiece holding body. Then, a placing head places the components on each of the plurality of workpieces which are subjected to posture adjustment.