A component mounting system that efficiently determines a component as a bulk component to be mounted on a bulk feeder through a simulation, and a bulk component determining method. The component mounting system includes a printed-circuit-board conveyance section that includes conveyance lanes and which convey a plurality of different types of printed circuit boards, a component supply section, a mounting head, a bulk feeder, and a bulk component determining section that performs a simulation in which operation times when the components supplied from the component supply section are moved on the printed circuit boards on the conveyance lanes are calculated for all the components and determines the bulk component to be mounted on the bulk feeder based on the calculated operation times.