Circular saw is a mechanized tool that uses a single-phase series excitation motor as the power, and then drives the circular saw blade through a transmission mechanism to perform continuous and uniform rotation motion for sawing operations. Circular saws are suitable for sawing wood, fiberboard, plastic, flexible cables, and similar materials. The circular saw adopts a portable appearance structure, mainly composed of a motor, gearbox, protective cover, adjustment mechanism and base plate, handle, switch, non- reconnectable plug, circular saw blade, etc.