To provide a technique means capable of receiving machining reaction or weight of upper and lower tool rests by a highly rigid and compact structure, regarding a lathe provided with a slant type bed, two spindles oppositely arranged on the same axis and the tool rests arranged on the upper and lower sides of a spindle axis to be movable on a Y-axis.

Two guide rails 25a and 25b for guiding an upper tool rest unit 41 are arranged at a position where a perpendicular V lowered from a center of gravity G of the upper tool rest unit 41 passes between the guide rails 25a and 25b. Two guide rails 26a and 26b for guiding a lower tool rest unit 42 are arranged at a position where a perpendicular U lowered from a cutting position of a workpiece by a tool mounted on the lower tool rest 38 passes between the two guide rails 26a and 26b.