The invention provides an automatic circular arc edge cutting device. The automatic circular arc edge cutting device comprises a base, a workbench arranged on the base, a rotary mounting piece which is arranged on the workbench and used for mounting and positioning a plate, a first drive device for driving the workbench to move on the base, a second drive device for driving the rotary mounting piece to rotate, a saw beam arranged on one side of the workbench and a third drive device for driving the saw beam to operate. During operation, the first drive device drives the workbench to move to the set position, the second drive device drives the rotary mounting piece to rotate so as to drive the plate to rotate, and the third drive device drives the saw beam to conduct edge cutting on the plate. According to the automatic circular arc edge cutting device, according to the size requirement of the preset plate, the workbench is driven by the first drive device and automatically positioned to the set position, and the edge cutting operation is conducted through the saw beam; and compared with traditional edge cutting devices, the automatic circular arc edge cutting device is easy to operate and high in efficiency.