An actuating device is provided, which includes a deformable membrane, walls formed on the membrane to define cavities, rods formed within the cavities, and on the surface of the membrane on one side with reference to a cavity center, to move in association with the deformation of the membrane, and an actuating unit formed on a lower side of the membrane to be piezoelectrically driven to deform the membrane. The actuating device is applicable to miniaturized electronic devices and can actuate the function modules appropriately.