Abstract. This paper proposes wave-shape pattern control method for whole-body deformable robots containing electroactive polymers. Mechanisms consisting of a typical electroactive polymer gel containing poly 2 -acrylamido -2- methylpropane sulfonic acid (PAMPS), named ’gel robots’, have been designed, developed, and controlled experimentally. We faced a common problem called, the degrees-of-freedom problem, namely controlling many points on the gel surface with a small number of inputs. In order to solve the problem, we once reduced the number of inputs to one, and discovered that wave-shape pattern evolves for the beam-shaped gel even in a constant uniform electric field. This method makes use of the pattern formation. Wave-shaped gels with varying curvature are obtained by switching the polarity of a spatially uniform electric field. The method is verified through experiments which are carefully designed based on numerical simulations.