PROBLEM TO BE SOLVED: To provide a rest device system which can support a processing place or cylindrical parts at its two ends with a high rigidity and which gives a large flexibility with a large versatility. SOLUTION: A table 14 on which a pair of work supporting devices 20 and 21 are placed, is provided in such a way as capable of indexing in the longitudinal direction, and at least one of the processing parts C1-C8 on a work W whose two ends are supported rotatably by the devices 20 and 21 is selectively indexed to the front face of a tool G. In this machine tool, a pair of rest devices 51 and 52 are furnished on the table 14 with possibility of locational indexing individually in their longitudinal direction, and it is arranged so that the journal parts at the ends of each processing part can be supported by the rest devices 51 and 52. Feed screws 36a and 36b to make locational feeding of the rest devices 51 and 52 are threaded through a tunnel 32 formed in one of the work supporting devices 21, extended to the back surface of the supporting device 21, and there coupled with servo motors for driving 46a and 46b.