Machining is possible in such a manner that an optional position of a workpiece is positioned just under a tool by rotation of a turn table in a C-axis direction, movement of the turn table in a Y-axis direction, and movement of a spindle in a Z-axis direction, so that a width of a main unit in a X-axis direction can be made shorter in comparison with machining by moving the turn table in the X-axis direction. Besides, the turn table located on a front side of the main unit, an ATC located on the rear side thereof, and a separated control panel located on the rear side of the ATC, independent from the main unit can also make the width of a machining center in the X-axis direction shorter.