Abstract: A vertebral body expanding device includes a bolt, a first nut, a second nut, a first supporting member, a second supporting member, a third supporting member, a fourth supporting member, a first expanding member and a second expanding member. The first nut and the second nut engage the bolt by two opposite screw threads. The first and third supporting members are pivoted to upper and lower ends of the first nut respectively, and the second and fourth supporting members are pivoted to upper end and lower ends of the second nut respectively. The first and second supporting members are pivoted to a lateral surface of the first expanding member, and the third and fourth supporting members are pivoted to a lateral surface of the second expanding member. The first and second nuts move toward or away from each other to retract or expand the first and second expanding members.