To perform data communication by infrared ray by exactly fixing the position of a handy terminal and the position of a printer without burdening a worker when performing a picking work.

An attachable/detachable attachment 17 is mounted on the truck. The attachment 17 is provided with a terminal holding member 72 for attachably/detachably holding the handy terminal 18 and a printer mounting member 73 for mounting the printer 19 for printing information transmitted by using infrared ray from the handy terminal 18. A hole 81 for communication is formed at a bottom part of the terminal holding member 72. Infrared ray transmitted from a light transmitter-receiver 31 of the handy terminal 18 held in the terminal holding member 72 is received by a light transmitter-receiver 35 of the printer 19 mounted on the printer mounting member 73 via the hole 81 for communication.