A mounting device, for mounting a plurality of buttons (100) on a product, includes a supporting member (30), a punching member (40), and a driving member (50) for driving the punching member. The supporting member includes a supporting panel (10), a plurality of holding portions (12) fixed on the supporting panel for supporting the product, a molding board (20) having a plurality of molding holes (22) corresponding to button holes of the product, a platform (32), and a base (34) fixed on the platform for supporting the molding board. The punching member includes a retaining member (42) positioned above the supporting member, and a plurality of cutters (44) fixed to the retaining member for cutting the buttons off a button assembly. Each of the cutters includes an axial through hole coupled to a vacuum generator for creating suction to hold the buttons on the cutters.