PURPOSE: To provide a machine tool which can make a variety of machinings as required by arranging its spindle so as to be capable of rotating in a wide range from low speed to high speed rotation.

CONSTITUTION: The spindle head 3 of a machine tool is equipped with a tilting head 2 for high speed rotation and another tilting head 1 for low speed rotation. A replacer body 13 is provided, in which tools to be mounted on the tilting head 2 are replaceable, while another replacer body 15 is furnished in which tools to be mounted on the other tilting head 1 are replaceable. Accordingly tools on the replacer bodies 13, 15 are replaced in compliance with the tools currently mounted on the respective tilting heads 1, 2.