1. A method for simulating a rubber material comprising a step of setting a rubber material model modeled on a rubber material including a matrix rubber, silica, and an interface bonding agent to bond them with numerically analyzable elements; a step of calculating deformation by setting conditions in said rubber material model; and a step of acquiring needed physical quantity from said deformation calculation; wherein said rubber material model comprises a matrix model modeled on the matrix rubber, a plurality of silica models modeled on said silica arranged in said matrix model, and an interface model surrounding annularly each of said silica models and having a harder physical property than said matrix model; and said rubber material model comprises a coupled body formed by coupling a plural of said silica models via said interface model.