Let be a smooth Banach space with a norm ‖ ⋅ ‖. Let ( , ) = ‖ ‖ 2 + ‖ ‖ 2 − 2 ⟨ , ⟩ for any , ∈ , where ⟨⋅, ⋅⟩ stands for the duality pair and is the normalized duality mapping. We define a -strongly nonexpansive mapping by (⋅, ⋅). This nonlinear mapping is nonexpansive in a Hilbert space. However, we show that there exists a -strongly nonexpansive mapping with fixed points which is not nonexpansive in a Banach space. In this paper, we show a weak convergence theorem and strong convergence theorems for fixed points of this elastic nonlinear mapping and give the existence theorem.