The invention discloses a plate splitting device, which is provided with a bracket, wherein a moving part which can move up and down is respectively arranged at two opposite sides of the bracket, a guide rod is transversely arranged on each moving part, two guide grooves through which two free ends of the guide rods are inserted respectively are vertically arranged on a stander, each moving part is provided with a through groove, an adjusting part is movably inserted into each through groove, the inner free end of each adjusting part is a support head, the outer free end of each adjusting part extends out of the corresponding through groove, the bracket is vertically provided with an adjusting groove, the inner side wall and the outer side wall of the adjusting groove respectively comprise an upper groove section, an oblique section and a lower groove section which correspond to each other, wherein the two oblique sections are oblique from top to bottom and from inside to outsides, the two oblique sections are staggered to each other up and down, and the oblique section at the outer side is higher than the oblique section at the inner side. The plate splitting device disclosed by the invention is simple in integral structure, easy to operate, continuous and reliable in plate splitting action, high in plate splitting efficiency, extremely little in damage to bricks in the plate splitting manner and flexible and adjustable for splitting plates and provides a brand-new operation mode for plate splitting operation of the plates with the bricks.