This paper analyzes optimization algorithms of assembly time for a multi-head mounter. The algorithm in this paper is composed of four steps. First, it assigns the components to feeders based on the "one-to-many mapping".Secondly, it assigns nozzles to heads by making full use of the "on-the-fly nozzle change" heads. Thirdly, it organizes the feeder groups so that the heads can pick and place components group by group. Finally, it assigns feeder groups to slots.The result demonstrates that the algorithm has good performance in practice.