A calculation method for finding the hole mobility or the electron mobility of an organic film. The method includes the steps of: calculating the electron density of a film using semi-empirical quantum molecular dynamics calculations; using the fact that holes and electrons move easily through regions of high electron density to calculate the probability that a hole or an electron will move in an excited state in which an electron is excited from the HOMO (highest occupied molecular orbital) to the LUMO (lowest unoccupied molecular orbital) using a Monte Carlo method; and, using the probability as a performance index, calculating the hole mobility from the number of carriers which exist in the HOMO and the orbitals below the HOMO, or calculating the electron mobility from the number of carriers which exist in the LUMO and the orbitals above the LUMO.