PURPOSE: To discriminate and sort the parts securely by air jet in a simple constitution, by blocking the through-holes in the discriminating stage provided in the same array as the plurality of through-holes furnished in the transfer route according to the shape of parts.

CONSTITUTION: When parts 21... reach a parts discriminating part 4 in a transfer route 1, the parts 21 ... are stopped by a shutter 6, and, at the same time, solenoid valve is opened to supply compressed air into the enclosed part of a discriminating stage 8. In the bottom of the stage 8 are provided through-holes b1, b2 ... in the same array as through-holes a1, a2 ... in the discriminating part 4, and the holes b1, b2 ... are partly closed depending on the shape of the parts 21, 22 ... Therefore, irregular parts are discriminated by the injection air from specific ones of holes a1, a2 ..., not conforming to the shape of parts 21 ..., which are connected to the holes b1, b2... with branch pipes 141, 142 ..., and at the same time, such parts are sorted as being blown off the transfer route 1. Thus, the parts may be securely and reliably discriminated in a simple constitution.