The present invention provides an accurate and high-precision semiconductor device simulation method that is directed toward an electronic device whose physicality is not isotropic because the mobility of an organic thin film transistor, that employs an organic semiconductor, and the like, is highly dependent on field strength. In a semiconductor device simulation method which divides a semiconductor device of a two-dimensional structure or three-dimensional structure into meshes, and solves physical equations such as a potential equation and a carrier transport equation, for the meshes, a drift current resulting from an electric field and a diffusion current caused by a carrier density gradient are handled separately.