To lay a cable and/or a hose through piping in a small space, irrespective of the number of pipes, without any influence on the operating speed of a pallet replacing device.

In this machining center 1, in a center shaft 17, a second center shaft 18 is provided which is moved up and down only with the vertical movement of the center shaft 17, and has an upper end projecting upward from the center shaft 17. To a center shaft disk 19 on the side of the center shaft 17, one end of a chain-type hose protection pipe 20 with horizontal flexibility is fixed, to hold a flexible hose 29 passing therethrough. On the other hand, the other end of the hose protection pipe 20 is fixed to an extension part 27 on the side of the second center shaft 18, at the same height as the one end and at the outer side than the fixation position of the one end. The flexible hose 29 passing through the hose protection pipe 20 is connected between an external pipe connection port 30 and an internal pipe connection port 31.