A tire is designed using a tire FEM model by obtaining an optimal solution for a tire structure which optimizes an objective function with a tread pattern shape kept fixed and performing a numerical optimization for obtaining an optimal solution for the tread pattern shape which optimizes the objective function with the tire structure kept fixed. The optimization for the tire structure is performed using a tire model having a tread pattern shape optimized at the immediately preceding cycle of the operation of optimizing the tread pattern shape. The optimization for the tread pattern shape is performed using a tire model having a tire structure optimized at the preceding cycle of the operation of optimizing the tire structure. The optimizing operations are repeated until convergence of optimal solutions obtained by those operations takes place.
