A shape deformation encoding device includes: a calculation unit for calculating a difference data between a pre-deformation shape data which represents a shape of an object before shape change and a post-deformation shape data which represents a shape of the object after shape change; and a determination unit for determining an action area on which the shape change of the object is arisen and an external force which is acted to the action area for the shape change, based on the pre-deformation shape data and the difference data. The action area includes a plurality of small areas, each of the plurality of small areas includes a plurality of control points, and the external force is calculated as an external force required to deform the plurality of small areas from before to after the shape change independently based on the physical model structure of each of the plurality of small areas. The physical model structure in which the plurality of control points are connected together with springs and dampers are used as a physical model structure.