To calculate tire performance with high accuracy, in simulation of a tire using a computer.

This simulation method for a tire includes a model forming step for forming an analysis model, a design variable setting step for setting design variables of the analysis model, a region dividing step for dividing the surface of a tire model into a plurality of regions, a deformation calculating step for executing deformation analysis of the analysis model based on the design variables having been set, a growth amount calculating step for calculating the growth amount of the surface of the tire model of the analysis model performed with deformation analysis based on the calculation result, an average and variance calculating step for calculating an average and variance of the growth amount with respect to respective regions divided, and a determining step for determining the analysis model based on the calculation result.