To provide a tool rest of a machine tool, which is insensitive to thermal displacement due to temperature change, and performs an accurate machining operation without carrying out complicated correcting calculations for a feed rate, etc.

The tool rest comprises a turret 4 having a plurality of stations S for attaching tools 9 thereto, and a tool rest indexing mechanism for indexing arbitrary stations of the turret 4 to a required machining position. A thermal displacement suppressing material 11 having the specific heat larger than that of the turret body 4A of the turret 4 is arranged in the station S of the turret 4 or in the neighborhood of the station S. The thermal displacement suppressing material 11 is stored in a thermal displacement suppressing material storing chamber 12 formed in the turret body 4A, for example, as a liquid such as cutting fluid. The thermal displacement suppressing material 11 may be a solid.