A machine tool is provided with a base, a tool rest and a boring bar magazine. The tool rest is mounted on the base and retains a boring bar. The tool rest is moved in a first direction in parallel with an axis of the main spindle and in a second direction perpendicular to the first direction. The magazine is located opposite to a headstock and stocks the boring bars and swivels and indexes the boring bar. The tool rest is moved whereby the boring bars are changed by other ones between the tool rest and the magazine. Thus, the tool rest is moved in at least two directions so that the boring bars are changed between the tool rest and the magazine.