To maintain a high precision over a long period of time by providing an almost frame-form annular column structured by integrally connecting, a floor frame and a main axial head frame and providing a bed structured in a freely attachable/detachable manner, with a floor frame.

An annular column 20 is formed almost in a frame shape, of a floor frame 22 which is disposed on the floor extending in the horizontal direction and a main axial head frame 21 which is supported by the upper end part of a columnar frame 23 extending upward from the upper face of the floor frame 22, connected together by welding. A bed 30 is separably connected to a connecting frame. A column manufactured separately from the bed 30 is made an annular column of an almost frame-form shape having a high rigidity structured of the floor frame 22, the main axial head frame 21 and the columnar frame 23. Thus the whole cutting machine is made lightweight, and is free from causing inaccuray in its conveyance. Further, installation work and fine adjustment of the machine at a factory can be done easily.