Solder resin composition comprising solder powder on the first electronic component (2) and (5a) resin (4) (6) is placed, the connection terminals of the first electronic component (2) and (3) the electrode terminals of the second electronic component (8) and (7) are arranged so as to face, included in the first electronic component by heating the first electronic component (2) the solder resin composition (2) gas source (1) is ejected gas from, by convection gas (9a) in the solder resin composition (6), is flowed solder powder (5a) in the solder resin composition (6), connected terminals (3) and the connection terminal (3) by self-assembly on the electrode terminal (7) and the electrode terminal (7) and to electrically connect the. This provides a bump forming method for mounting a flip chip mounting method and the circuit board to the connection terminal of the electrode terminals and the circuit board wiring semiconductor chip can be connected with high connection reliability at a narrow pitch.