A machine tool is disclosed. The machine tool includes a robot which is compact and which enables easy use of different end effectors for respective purposes. An internal robot includes a plurality of joints that are composed of a base joint and parallel joints, and a plurality of links. The distal end is split into two or more branches, each having a tool changer. An end effector is detachably attachable to each of the tool changers. Rotation of the base joint causes a change between a first tool-following position and a second tool-following position, so that different end effectors are used for respective purposes by using an end effector attached to a tool changer in the first tool-following position and using an end effector attached to another tool changer in the second tool-following position.