The utility model provides a centering clamping device which is compact in structure and favorable for reducing occupied space, and relates to a clamping device. A centering clamping device comprises a support, a clamping driving cylinder, a left clamping block, a right clamping block, a left swing arm and a right swing arm. A supporting block used for supporting a workpiece is arranged on the support, and the left clamping block and the right clamping block are arranged on the two sides of the supporting block respectively and are oppositely arranged. The left swing arm is arranged on the side, provided with the left clamping block, of the supporting block, the right swing arm is arranged on the side, provided with the right clamping block, of the supporting block, and the left swing arm and the right swing arm are hinged to the support through hinge shafts arranged between the upper ends and the lower ends of the left swing arm and the right swing arm respectively. A gap is formed between the left swing arm and the right swing arm to form a clamping driving cylinder mounting space, and the clamping driving cylinder is inversely mounted in the clamping driving cylinder mounting space. According to the device, the occupied space in the longitudinal direction and the transverse direction is small, and the installation and use requirements in the small space can be better met.