A bony expander comprises two support parts, a scalable member, and a fastener. Each of support parts comprises one fixing portion and two support portions. The fastener fastens the fixing portion of these two support parts to form a cavity. The scalable member is provided in the cavity. The scalable member comprises a nuts and a bolt. Moving the nuts or the bolt can change the length of the scalable member. When the length of the scalable member becomes long, the outer end portions of the scalable member are pushed against the four movable support portions so that the four movable support portions are distracted simultaneously. Thereby the collapse bone is distracted.一種骨撐開裝置,包含二個撐開部件、螺栓組、以及扣件,每一個撐開部件包含二個活動部以及固定部,扣件緊固二個撐開部件的固定部以形成腔體,螺栓組設置於腔體中,螺栓組包含螺母件以及螺公件,移動螺母件或螺公件能改變螺栓組的長度,當螺栓組的長度變長時,螺栓組的外端部分別抵推四個活動部,使四個活動部同時被撐開,藉以使塌陷的骨被撐開。10‧‧‧骨撐開裝置32‧‧‧撐開部件3202‧‧‧活動部3204‧‧‧固定部3206‧‧‧變形部34‧‧‧扣件36‧‧‧螺栓組3602‧‧‧螺母件3604‧‧‧螺公件36H‧‧‧操作軸孔36S‧‧‧槽孔36T‧‧‧外端部
