To improve the operation efficiency by controlling a moving robot to move to a charging station while performing operation at a work station when the work station is present between the current position and charging station.

At dedicated parts of 1st and 2nd lines L1 and L2 between a branch point D1 and a branch point C1, two work stations ST4 and ST5, and ST6 and ST7 each are installed. A charging device is provided at each of the work stations ST5 and ST7 for each of the lines L1 and L2 and the stations ST5 and ST7, therefore, function as work stations where a 1st robot 2 for line operation and a 2nd robot 2b for line operation can be charged while operating. When there is a work station between a current position and a charging station on a travel path like this, a robot is so controlled as to move to the charging station while operating at the work station.