PURPOSE: To reduce running cost of a complicated and long conveyor system, by automatically traveling a truck equipped with a rope clamping device along an endless driving rope set on a path linking preset stations.

CONSTITUTION: A traveling path of a truck, linking cargo handling stations 1W7, is divided into two routes A, B, each being equipped with endless wire ropes 13, 14, respectively. The wire rope travles in a groove below a floor 10 and drives a truck 9 which has a rope clamping device on its front end. The rope clamping device can be pulled up through links 47, 48 from the groove, or each pair of rollers 62, 72 is engaged with a cam for releasing or selecting the rope automatically. This conveyor system can reduce its running cost, because it can drive trucks without congestion, even if the path is complicated.