Abstract: A workbench has a bench frame, a rack seat disposed on the bench frame, and a screw rod passing through the rack seat, a positioning block, a hollow shaft, a coiled spring, and a T-shaped sleeve. The rack seat has a slide slot. The T-shaped sleeve, the hollow shaft, the coiled spring, and the positioning block are disposed in the slide slot of the rack seat. A first sliding seat is disposed on the T-shaped sleeve. A second sliding seat is disposed on the positioning block. A first clamping block has a first bottom post inserted in the first panel. A second clamping block has a second bottom post inserted in the second panel. A first rivet passes through the first panel, the first sliding seat, and the T-shaped sleeve. A second rivet passes through the second panel, the second sliding seat, and the positioning block.