An object of the present invention is to provide solder bumps sufficiently satisfying the expected functions and having a small diameter which conventional methods cannot attain, a semiconductor device on which these bumps are mounted, and a bump transferring sheet. The present invention provides a method for forming the bumps, which includes forming a solder alloy material layer and flux material layer one by one on an intermediate metallic layer formed on an external electrode pad in a semiconductor device, and then fusing these layers, wherein each of the solder alloy material layer and flux material layer is formed by a liquid spraying method (e.g., ink jetting method).