FIGS. 9A and 9B are a perspective view and a flow chart of an apparatus according to the fourth embodiment wherein component cassettes 400 accommodating electronic components for SMT mounting, e.g. Die Bonding (D/B), are arranged at the left side of the board stage 17 of the apparatus in FIG. 6 and the first and second component carrier heads 11 and 13 are arranged in the same fashion as FIG. 1.