PURPOSE: To improve the reliability of lead frame soldering without sticking a liquid resin to the part upper than a stand-off by pumping up the liquid resin, ejecting the liquid resin from a nozzle and coating the resin to the rear surface of a hybrid integrated circuit.

CONSTITUTION: The ejection port of the nozzle 1 is provided toward the aperture of a tank 4 and a circuit board 7 is inclined with a lead frame 6 side faced upward. The liquid resin 5 passes a pipe 3 and is ejected from the nozzle 1 when the pump 2 is operated after the circuit board 7 is brought to the under side of the nozzle 1. The ejected resin sticks to the circuit board 7 on the rear side of the hybrid integrated circuit and electronic parts 8 on the rear side. The coating on the rear side surface of the circuit board 7 is executed by the gradual movement of the resin from above to below, by which the liquid resin 5 is coated on the rear surface and the packaged electronic parts 8. The coating is thus executed without sticking the resin to the part upper than the stand-off 9 by previously adjusting the rate of the ejection from the nozzle 1 and the viscosity of the liquid resin.