Provides a solder ball loading unit capable of loading fine solder balls on electrodes. Solder balls 78s are gathered by sucking air from a loading cylinder 24 located above a ball arranging mask 16. The gathered solder balls 78s are rolled on the ball arranging mask 16 by moving the loading cylinder 24 in a horizontal direction and the solder balls 78s are dropped onto the electrodes 75 on a multilayer printed wiring board 10 through an openings 16a in the ball arranging mask 16.
