With multiple-board substrate defined as a circuit substrate provided with multiple boards of circuit pattern on which multiple electronic components are mounted, when performing mounting work of multiple electronic components on a multiple-board substrate using three mounters lined up in a row, electronic component mounting work procedures are set such that mounting work of electronic components for each of multiple circuit patterns is performed by all three mounters. Work procedures for mounting work of electronic components surrounded by the dashed lines are set to a first mounter, work procedures for mounting work of electronic components surrounded by the single-dashed solid lines are set to a second mounter, and work procedures for mounting work of electronic components surrounded by the double-dashed solid lines are set to a third mounter.