To provide a method for processing a carbon fiber material for accurately processing a material including the carbon fiber by machining, well performing processing with high processing surface accuracy and improving the service life of a tool.

In the method, a workpiece W of a material including the carbon fiber is processed. A machine tool in which a table 12 mounted with the workpiece W thereon and a rotatable spindle 19 are constituted to be relatively movable in at least one axial direction is prepared. An electroplated tool 30 having a cylindrical tool body, a cutting blade part formed on an outer periphery of the tool body and an abrasive grain layer fixed with abrasive grains fixed by electrodeposition to a surface of the cutting blade part is mounted on the spindle 19 of the machine tool. While rotating the spindle 19 and relatively moving the spindle 19 and the table 12, the workpiece W is processed by the electroplated tool 30.