To check address setting in each display unit in a picking device by which multiple kinds of articles stored in respective shelves are efficiently sorted according to respective destinations in an article collection/distribution center.

By means of a host computer 10, a test command for a connection check is fed out after a system of a picking device is completed. When each display unit 15 receives the test command, all of the display lights of the display unit 15 are turned on. An address of a unit in which a reset switch is pushed is transmitted, and the display light is turned off. The transmitted address information is displayed by means of the host computer 10. This process is repeated, and as a result, address setting in each unit can be checked.