Machine tool

A machine tool comprising:

• a headstock that is arranged in a working chamber and holds a workpiece so as to be rotatable around a workpiece rotation axis parallel to a horizontal direction;
• a tool post that is arranged in the working chamber in such a way as to be movable in a first axial direction parallel to the workpiece rotation axis and in a second axial direction orthogonal to the first axis, and holds a tool;
• a robot that is arranged in the working chamber;
• a cover that surrounds the working chamber;
• an opening of the cover for communicating the inside and the outside of the working chamber;
• and
• a door that opens and closes the opening,
• wherein the robot includes a root joint fixed in the working chamber, and a link unit positioned on a distal end side of the root joint and having multiple links that are articulated with each other, and
• the root joint is a linear-motion joint that is extendable in a direction orthogonal to the workpiece rotation axis, and is a linear-motion joint that is extendable between the length for causing the entire link unit to be positioned inside the working chamber and the length for causing the entire link unit to be positioned outside the working chamber.