PURPOSE: To apply the minimum quantity of flux required for soldering to only a part to be applied with the flux by inserting leads of electronic parts by a holding member into grooves provided on the upper surface of a movable member in which the flux is filled up and applying the flux thereto.

CONSTITUTION: The holding member 8 holding the electronic parts 7 is moved to the position where the leads 7a and grooves 6 are opposed to each other by a driving mechanism and a package 7b of the electronic parts 7 is lowered vertically till the position not to come into contact with the upper surface of the movable member 2. Accordingly, the flux 10 filled up in the grooves 6 is applied to places where the leads 7a come into contact with a pattern of a printed board. When the flux 10 is applied to the leads 7a, the holding member 8 is moved to the position where the electronic parts 7 of the printed board to which these electronic parts 7 are fitted are fitted while the electronic parts 7 being held by the driving mechanism and the electronic parts 7 are fitted thereto. Accordingly, the minimum quantity of flux required can be applied to the leads 7a.