To provide a flexible automatic conveyance system between processes, operating at a low cost while enhancing flexibility in changing layout, and suitable for automatically conveying a workpiece.

The flexible automatic conveyance system between processes has: work station kits 100 arranged correspondingly to a plurality of machining centers 10; rail kits 200 for connecting them; turn kits 300 arranged between rail kits or between a rail kit and a work station kit; a workpiece input kit 410 connected to a rail kit or a work station kit; a workpiece discharge kit 420 connected to a rail kit or a work station kit different from the one the workpiece input kit is connected to; and a plurality of workpiece carrier vehicles to move on the kits connected to each other. The rail kit is attachable to and detachable from the work station kit, the turn kit, the workpiece input kit, and the workpiece discharge kit.