PURPOSE: To improve rigidity without enlargement in a lathe, in which a bed upper surface is tilted due to the natural drop of a chip.

CONSTITUTION: This frame structure is applied to a lathe, which is having a main spindle 2 in parallel to the width direction of a bed 1 and in which a work working region B on the upper surface of a bed 2 is downwardly tilted forward. In such a lathe, part or the whole of a head stock 6, supporting a main spindle 2, is made a cast item integral with a bed 1. A width direction part 1a, in which the head stock 6 of a bed 1 is arranged, is protruded forward beyond the width direction part 1b in the work working region B to expand a depth dimension. A chip receiver 19 is located on a floor surface in the front of the work working region B.