The palladium plate form changing during its one-side saturation with hydrogen at temperatures 320°C in a wide range of pressures, $P_{H_{2}}$ = 0.01—0.3 MPa, is experimentally studied. There is confirmed that the form changing of the plate is developed in two stages. At the first stage, the plate quickly reaches its maximum bending. At the second one, much longer than first, the plate straightens. This straightening is almost completely reversible. As revealed, the maximum deflection of the plate depends nonlinearly on the hydrogen pressure in those cases when hydrogen pressures are low. This dependence corresponds to the formation of the ideal and pseudo-ideal solutions of hydrogen in palladium. The physical nature of the discovered experimental dependences is discussed. Efficiency of the previously developed phenomenological model is confirmed.