To achieve efficient machining without causing wasteful processes even when machining a variety of workpieces with a different number of machining processes, and to materialize a simple replacement without increasing man-hours even when replacing dies.

A press line 1 is formed by arranging long sides of a plurality of press devices P1-P4 so as to be parallel with an array direction. A travelling rail 51 is provided orthogonally to the array direction with respect to respective press devices P1-P4 so as to allow the travel of a self-propellent bolster 52 loaded with a die D to be utilized next. The lower surface of a crown 3 overhanging an upright 2 is provided with handling robots 30a-30f. The intermediate part between the line and the upstream side of the press device P1 in the initial process are provided with workpiece charging seat loaders 10a, 10b. The intermediate part between the line and the downstream side of the press device P4 in the final process are provided with carry-out conveyors 20a, 20b for workpiece delivering.