PURPOSE: To smooth the movement of a conveyed article and heighten the efficiency of the conveyance, by obliquely providing a pair of conical shafts so that a uniform gap is defined between them and by rotating the shafts in opposite directions to move the conveyed article supplied from a large-diameter section, while truing up the article.

CONSTITUTION: For example, in a screw inspector 10, screws (a) are supplied to a sorting section 11 by a conveyor 16. Screws with heads of too small diameter are removed at a large-diameter section 13. Screws with heads of too large diameter are removed at a small-diameter section 15. Only screws with heads of proper diameter drop from a medium-diameter section 14 and are conducted to a conical-shaft conveyance section 18, in which, because of the slopes and opposite rotation of conical shafts 19, the screws are sequentially moved to a straight movement feeder 22 while the screws are trued up so that their heads are placed at upside. At that time, screws not trued up are blown away by an air nozzle 20 and returned to the sorting section 11 by a conveyor 21. In the straight movement feeder 22, the screws are moved through a prescribed inspection stage and divided into a good and a bad groups by a separator 24.