Two-dimensional off-lattice behavior of chainlike self-driven objects is numerically studied. The objects undergo spontaneous, irreversible aggregation, irrespective of their deformability, in contrast with the on-lattice case in which aggregation is observed only when the objects are deformable. Also, we found that the tendency of aggregation increases with the decrease in the degree of deformability of each object or with the increase in the degree of fluctuation.