An internal rocking structure applied in eyeball of the puppet includes an outer casing made of a transparent material, an inner casing, and an elastic member; the inner casing being connected to the elastic member, which is connected to a bottom of the outer casing; a pattern of an eyeball being printed on where appropriately on the inner casing; upon shaking the rocking structure, the elastic member maintaining the inner casing in a rocking status for a given time to deliver amusing effects of a rocking eyeball and significantly increase bizarrely lovable effects when applied in a puppet or doll.