According to the present invention, even during and immediately before a machining operation by a machining apparatus, it is possible to improve positioning control accuracy thereof and, as a result, machining accuracy thereof. A robot 11 equipped with a machining tool 12 performs a moving operation to a target position 41 of a machining target workpiece 2 and a machining operation on the machining target. A robot moving mechanism 14 moves the robot 11 in parallel with the workpiece 2 that is being conveyed by a conveyance carriage 18. A robot control device 17 controls movement of the robot moving mechanism 14 using a detection result of a synchronizing sensor 15 and carries out positioning control of the robot 11 using the detection result of a visual sensor 13 or a synchronizing sensor 15.