Electrochemomechanical deformations (ECMD) of polyaniline film have been enhanced in hydrochloric acid (HCl) equilibrated in pH 1.2 with sodium chloride (NaCl). The maximum film deformation has been reached to 7%, which is two times larger than that observed in 1 M HCl. Taking the pH dependence of redox-potential into account, this enhancement can be explained by the increase of anion doping ratio.