A method to easily and economically manufacture more precise patterns compared with usual MEMS technique has been searched for. Under such circumstances, this research aims to clarify the formation of nano-scale protrusion structure produced by local anodic oxidation on Si wafer surface in expectation of the nano/micro mold production for nanoimprint lithography in future. In this report, the influences of contact width and distance between probe tip and Si wafer surface (distance between terminals) on the size and shape of protrusion patterns were examined in order to clarify the fundamental phenomena in local anodic oxidation. A scanning probe microscope equipped with a current measuring unit was utilized in local anodic oxidation experiments. As a result, it was confirmed that the size of generated protrusion structure became larger with increasing the contact width and became smaller with increasing the distance between probe tip and Si wafer surface. These facts will be useful in producing 3-D nanostructures in future.