PURPOSE: To prevent a semiconductor device from being caught by providing sensors above and below a relay sorting rail respectively in a transport device and slightly moving the rail in the positive and reverse directions when the passing of the semiconductor device is not detected by the sensors in a predetermined time.

CONSTITUTION: A semiconductor device 1 is transported with leads 3 astride an upper chute 11 and with an envelope 2 depressed by a presser rail 11', and it is hooked by a stopper 17 when it is dropped to a relay sorting rail 12. The semiconductor device 1 is released from the hooking and is dropped when the rail 12 is shifted directly above one of multiple lower chute rails 13 via drive means 14W16. In this case, photoelectric sensors 21, 22 detecting the passing of the semiconductor device 1 are provided on the upper ends of individual rails 12, 13. When either of the sensors 21, 22 fails to detect the passing of the semiconductor device 1 within a predetermined time period, the rail 12 is slightly moved in the positive and reverse directions to prevent the semiconductor device 1 from being caught.