According to the present invention, the operating rate of a machine tool can be increased. Solution is made by a machine tool including a processing chamber surrounded by cover walls to perform processing of a workpiece to be processed, an equerre a part of which is arranged inside the processing chamber, the equerre fixing the workpiece, an opening arranged at a part of the cover walls for access to an inside of the processing chamber, and shutter doors movable between open positions where opening of the opening is performed so that the inside of the processing chamber communicates with an outside of the processing chamber, and closed positions where closing of the opening is performed so that the inside of the processing chamber is isolated from the outside of the processing chamber.