To easily and accurately operate a transfer belt by a worker.

A motor truck is provided with a baggage carrying-in and out device 2 wherein a packing case 1 is mounted on a car body, and a transfer belt 22 is provided on a floor surface of the packing case 1 so as to reciprocate in a longitudinal direction of the package case 1 by driving a driving means having driving chains 23. In such a constituted motor truck, a detected body or a plurality of detected bodies are arranged on the driving chains 23 with a predetermined space, a detecting body LS1 for detecting the detected body is provided on the floor surface of the packing device 1, and the driving means is drivingly controlled on the basis of detection of the detected body by the detecting body LS1. Moreover the driving means is drivingly controlled on the basis of the result detected of a detecting means by providing the detecting means for detecting a driving amount of the driving means.