PURPOSE: To detect the quantity of articles remaining on picking shelves without providing any residual article detector at each frontage of the picking shelves.

CONSTITUTION: A case C containing a plurality of articles is positioned at each frontage 2 of picking shelves 2, and the articles are taken out through a delivery port 3 for storage in a bucket B on a zone conveyor 4, according to picking data written on an ID card provided in the bucket B. The picking data is read by an ID card reader 9. After the storage work, the bucket B is pushed out to a main conveyor 8, and another ID card reader 11 reads the picking data of the bucket B in a work completion state. A control device stores the data of the articles stored on the picking shelves 1 in advance, and can detect the residual quantity thereof by deducting the quantity of picked articles.