Abstract: A machining center adapted for use in cutting a workpiece into a desired shape, comprising: a bed having a table for changeably holding a first pallet; a support die disposed in front of the bed to support a second pallet to be changed with the first pallet; a machine housing extending upwardly from the bed to define a cutting compartment enclosing the first pallet, the machine housing having a frontal access opening; a rotary door mounted on the machine housing to openably close the access opening; pivot pins for pivotally supporting the rotary door at central top and bottom edges of the door; a pallet changer disposed beneath the rotary door for exchanging the first and second pallets with each other, the pallet changer including a rotary arm, a vertical cylinder for causing the arm to vertically move from a lower position to an upper position and first and second horizontal cylinders for causing the arm to rotate between a first angular position where the arm remains parallel to the door and a second angul