Part Orientation Systems is used for automatically checking attitudes of individual parts which are successively transferred along a parts feeding track of a parts feeder. The system includes photoconductive detecting element mounted at one side of a predetermined detecting position on the feeding track and normally exposed to light incident thereon across the feeding track. It has an adaptable circuit means for activating parts rejecting means to remove a part from the feeding track depending on the signals from the detecting elements. The system also includes a spacing means for spacing apart the parts which successively pass the detecting position.