To machine different work positions of a workpiece by use of a common head by providing a rotating main spindle head having a horizontal main spindle and a vertical main spindle orthogonal to the horizontal main spindle and rotatable around the horizontal main spindle.

An end mill 59 is installed to the horizontal main spindle 14 of a rotating main spindle head 13. End surface cutting and tenon machining are performed to the end surface H of a rail material R by the end mill 59. A drill 60 housed in a vertical main spindle grip 54 is installed to the vertical main spindle 15 of the rotating main spindle head 13, and a through-hole K3 is formed on the strip bottom plate material R1 of the rail material R by the drill 60. The rotation of the vertical main spindle 15 is performed by an index mechanism.