To high-efficiently support a cam shaft material in a state that an axial position and a peripheral position are determined in a specified state as the material is horizontally maintained when the shaft end of a cam shaft material is machined.

The axis of the cam shaft material 10 is horizontally supported by a pair of horizontal support mechanisms 38A and 38B situated on a machine bed 36 in a position separated in the axial direction of the cam shaft material 10. By nipping a flange 10a, with which the cam shaft material 10 is provided, from the both sides in the axial direction of the cam shaft material 10 by an axial positioning mechanism 39, the axial position of the cam shaft material 10 is determined in a specified state. By nipping a protrusion, with which the cam shaft material 10 is provided, from both sides in a peripheral direction of the cam shaft material 10 by a peripheral positioning mechanism 40, the peripheral position of the cam shaft material 10 is determined in a specified state.