A method of simulating a resist pattern according to an exemplary embodiment includes a step (A) of calculating a latent image of a concentration of an active species in a resist film that has been radiated by a radioactive ray along a target pattern with respect to a radiation position of the radioactive ray, a step (B) of calculating a change rate of the concentration with respect to the radiation position at an edge of the target pattern on the basis of the latent image, a step (C) of calculating a probabilistic variation at the edge of the target pattern, and a step (D) of calculating a variation in pattern edge roughness from the change rate of the concentration and the probabilistic variation.