PURPOSE: To shorten rest time, enable a complete external setup and enhance production efficiency by building a pressing means into a lower tool rest and loading an upper tool rest monolithically on the lower tool rest for exchanging both tool rests.

CONSTITUTION: A pressing means 9 is built into a lower tool rest 7 and a cutting workpiece is pressed with a hydraulic cylinder 9b via a presser plate 9a. First, a slide 3 is lowered to a bottom dead center and a hydraulic clamper 5 is released. An upper tool rest 4 is released from the slide 3. Then, another hydraulic clamper 10 is released and an elevating rail 11 is moved upward and the lower tool rest 7 is lifted. The rail 11 loaded with the upper tool rest 4 is further lifted, thereby causing a locating pin 19 to be engaged with a hole 20. Thereafter, the fork part of an exchanging cylinder is hooked to a hooking part 7b. The exchanging cylinder is thereby made to advance and the tool rests 4 and 7 in a common loaded condition are moved on a fixed rail 13 to be shifted to a tool exchanging carriage, thereby exchanging the tool rests 4 and 7 for other tool rests.