The present invention improves a work efficiency of an entire system for operating a plurality of working machines. An operation system of the working machine includes a work progress calculating unit 80 which calculates a work progress of a plurality of working machines or a scheduled ending time calculating unit 81 which calculates a scheduled ending time of a work by using the work progress calculated by the work progress calculating unit 80. A working machine of which an operation is switched from automatic control to remote control is determined from among the plurality of working machines by using the work progress or the scheduled ending time, and the operation system includes a centralized operation controller 43 which transmits an operation instruction to the determined working machine.