Machine tool

A machine tool comprising:

• a support table provided on an upper surface of a bed to support a work;
• a Z-axis saddle for reciprocation in a longitudinal Z-axis direction;
• a machining unit mounted on the Z-axis saddle and provided with a machining head for machining of the work;
• a compartment cover arranged on the bed to compartment a machining region, in which the work supported on the support table is machined, and a machine region, in which the machining unit is movably arranged;
• an opening window provided on the compartment cover to permit the machining head to go in and out of the machining region therethrough;
• and
• a seal member in the form of a closed ring to be mounted on an inner peripheral edge of the opening window of the compartment cover;
• wherein an entire periphery of an outer peripheral surface of the machining head is brought into sliding contact with an inner peripheral edge of the seal member in a state, in which the machining head is moved into the machining region from a tool exchange position within the machine region.