Local electric conductive properties of Si nanowire models are investigated by using two local electric conductivity tensors, sigma(<->)(ext)((r) over right arrow) and sigma(<->)(int)((r) over right arrow), defined in Rigged QED. It is emphasized that sigma(<->)(int)((r) over right arrow) is defined as the response of electric current to the actual electric field at a specific point and does not have corresponding macroscopic physical quantity. For the Si nanowire models, there are regions which show complicated response of electric current density to electric field, in particular, opposite and rotational ones. Local conductivities are considered to be available for the study of a negative differential resistance (NDR), which may be related to this opposite response. It is found that sigma(<->)(int)((r) over right arrow) shows quite different pattern from sigma(<->)(ext)((r) over right arrow), local electric conductivity defined for the external electric field. The effects of impurities are also studied by using the model including a Ge atom, in terms of the local response to electric field. It is found that the difference from the pristine model is found mainly around the Ge atom. Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License. [http://dx.doi.org/10.1063/1.4769887]