PURPOSE: To enable efficient sorting by constituting a sorting apparatus of a detection part and a sorting part and constituting the detection part of a head block having a support shaft and a guide part and the proximity switch provided in opposed relation to the support shaft.

CONSTITUTION: A detection part 2 is constituted of a freely up-and-down movable support shaft 10, the head block 11 having a guide part 22 gradually going upwardly on the upstream side of the feed direction of a product 90 to be sorted provided to the under surface thereof and connected to the lower end of the support shaft 10 and the proximity switch 13 provided in opposed relation to the upper end of the support shaft 10. When the product 90 to be sorted is fed to the detection part 2, the upper end of the product 90 to be sorted comes into contact with the guide part 22 of the head block 11 and the head block 11 is raised to the position of the height of the product 90 to be sorted with the movement of the product 90 to be sorted. When the rear end of the support shaft 10 is measured by the proximity switch 13, it is detected whether the height of the product 90 to be sorted enters a tolerance range. Then, the product 90 to be sorted passes through the detection part 2 to be sorted as a good or bad product in a sorting part.