The circular saw is a machine for longitudinally or transversely sawing wood, metal, plastic or other materials. It is equipped with an electric motor that rotates a circular blade at high speed. Using a suitable blade (in terms of hardness and tooth shape), a portable circular saw can cut a wide variety of materials.

They are characterized by making precise cuts. In addition, some models allow cutting at an angle of up to 45 degrees and incorporate protection against dust or sawdust that is produced during the cut; some are prepared to connect to an external extractor.

On March 27, 1816, Auguste Brunet") and Jean-Baptiste Cochot") filed a patent for a circular saw (the organ builder Aristide Cavaillé-Coll had already created a circular saw before, but without filing the patent). Originally, the first circular saws, powered by water, only cut wood (Cavaillé-Coll's was also used to cut tin strips to make organ pipes). They can now also cut other materials by changing the blade type.