PURPOSE: To make it possible to make the sampling operation automatic by sampling the grains packed in jute bags, which are conveyed by a conveyor, with the use of a grain picker, which is moved back and forth at a right angle with respect to the conveying direction.

CONSTITUTION: When a jute bag 4, which is filled with grains and which is being conveyed by a conveyor 1, is detected by a sensor 19, a grain picker 8 on a hopper 6 is moved at an angle of depression of 8 to 30 degrees through an air cylinder 4 at a right angle with respect to the moving direction of the conveyor 1. The picker 8 is extracted from the bag 4 and then is returned, after it is inserted from the upper portion so as not to scatter the grains from the bag 4. The picker 8 is composed of a sliding pipe 11, which is operative to slide a thin rod 10 having an outside diameter smaller than 10mm and formed with a hole 13 and the like so as to effect the fitting by the pneumatic force, and the rod itself 10 formed with a grain accommodating hole 12. Thus, the grains in the respective portions in the bag 4 can be well sampled and stored. Thus, the sampling operation can be effected easily and reliably in an automatic manner.