Abstract: The machine tool comprises a vertical post (14) on which a head changer (19) is mounted for changing the tool head (17) provided at a head carrier (16). The head changer (19) is rotatable about a vertical axis. It carries at least one head gripper (22) which is adapted to grip from the top the tool head (17) and to rotate it from a front working position to a rear changing position. The post (14) being nonrotational (about any axis) and preferably unadjustable in height (the Y axis), is simple and low cost. The machine tool is readily adaptable to sophisticated design modifications, particularly including tool exchange in plural multi-tool tool heads and interchange with tool and/or tool head storage magazines.