A vertical movement device for an examining table includes a driving wheel, a nut and screw pair and a direction-converting synchronization belt. The driving wheel is disposed on the examining table. The rotation axis of the nut is perpendicular to the rotation axis of the driving wheel, and the nut moves vertically on the screw when the nut rotates so as to carry the examining table to move vertically. The direction-converting synchronization belt converts the rotation of the driving wheel into the rotation of the nut so as to realize the vertical movement of the examining table. The self-locking vertical movement device reduces the noise and manufacturing costs, simplifies the structure, increases the maximum lifting weight and speeds up the lifting/lowering process.
