PURPOSE: To carry out automatic mounting for a flexible printed board with high accuracy and efficiency, by previously drilling a hole at a given position in a weakly adhesive base sheet used for sticking the flexible printed board.

CONSTITUTION: As an example, in an automatic mounting machine, a flexible printed circuit board(FPC) 2 that is temporarily stuck in a given place of a weakly adhesive base sheet 1 is pushed up by a projected part of a pin jig 5 at a given position of the automatic mounting machine through a hole 4 drilled in a given place of the base sheet 1. After the FPC board 2 is lifted up from the weakly adhesive base sheet 1, the PFC board 2 is picked or sucked by a chuck member 6 or a suction member 7 at a suitable point of the automatic mounting machine and the FPC board 2 is carried to a given position. In this way, the FPC board 2 closely stuck to the base sheet l is lifted by the pin jig 5 so that the FPC board 2 is removed efficiently, and the automatic mounting is carried out with high accuracy and efficiency.