Machine tool

A machine tool comprising:

• a machine body for machining a workpiece;
• a machine body cover surrounding a periphery of said machine body;
• a machining-area opening formed in said machine body cover and opening a machining area of said machine body;
• and
• a door device opening and closing said machining-area opening,
• wherein said door device includes a first door to cover said machining-area opening when machining the workpiece and a second door disposed on an outer side of the first door and said second door being capable of covering said machining-area opening when not machining the workpiece, the second door being formed so as to allow observation of the machining area,
• wherein the first door and the second door have respective substantially vertical wall portions, the vertical wall portions being arranged to overlap when viewed from a side of said machine body,
• wherein the vertical wall portion of the second door includes a window portion larger than a window portion of the first door,
• wherein the first door and the second door are arranged so as to be movable between a position-in-use where each of the first and second doors is covering said machining-area opening and a position when opened opening said machining-area opening, and
• wherein during the machining, said machining-area opening is covered by the first door or by the first door and the second door, and during non-machining and during low-speed-rotation machining, said machining-area opening is covered only by the second door.