To provide a method for generating tray data of a surface mounter for no tray part suction point measurement error, data generation error, and part suction failure, while part suction error as well as mounter suspension caused by it and the like are reduced in a surface-mounting process.

A suction pad 2 of a surface mounter is provided with a CCD camera 1 with a prescribed offset. The surface mounter is operated to acquire a suction point for a part 11 of a tray 10 using the CCD camera 1, and data are inputted in a memory of the mounter. A calculation means provides a tray suction point pitch, based on the input data of a tray suction original point P1 acquired by the CCD camera 1, a final tray suction point (PXn, PYn), and X-direction column number Xn and Y-direction row number Yn of the tray 10. The tray suction point pitch acquired by the calculation, the tray part suction original point P1 inputted as data, and the final tray suction points (PXn, PYn) are used to generate a tray data comprising all the tray suction points.