The invention is directed to prevention of interference of an operation of mounting proper electronic components and improvement of usability without reduction of a manufacturing speed of printed boards. Suction states of electronic components held by suction by suction nozzles are detected by a line sensor unit. When the detection result shows that there is an improper electronic component, the improper electronic component is disposed of, and after the disposal a component recognition camera takes images of electronic components judged proper as a result of the detection and a recognition processing device performs a recognition process. When the recognition result shows that there is an improper electronic component, the improper electronic component is disposed of, and after the disposal only electronic components judged proper as a result of the recognition are mounted on a printed board.