The present invention provides a machine tool making it possible that an operator needs to remove a key member from a predetermined position after an unlock condition of a door is established when a door lock mechanism brings the door into an unlocked state, meanwhile the operator can recognize the necessity of reattaching the key member to the predetermined position when the door lock mechanism brings the door into a locked state. In the machine tool, an interlock mechanism 5a allows a door lock mechanism 8 to bring a door 3 into the unlocked state in a state that the unlock condition of the door 3 is established and when the key member 9 is removed from the predetermined position and, after the door 3 is unlocked, allows the door lock mechanism 8 to bring the door 3 into the locked state only when the key member 9 is attached to the predetermined position in a state that the door closed state detection mechanism 7 detects that the door is located at the predetermined closed position.