A solder ball mounting method includes a step of providing a flux on electrodes of a substrate, a step of arranging a plurality of solder ball mounting masks in which ball feeding openings are formed in positions opposing to the electrodes and opening areas of the ball feeding openings are set to increase toward an upper layer on the substrate, a step of mounting solder balls on the electrodes by feeding the solder balls into the ball feeding openings while moving the solder ball mounting mask as an upper layer in a surface direction of the substrate, a step of removing the solder ball mounting masks from the substrate, and a step of joining the solder balls to the electrodes.