To provide a cutting device devised to improve cutting efficiency by achieving optimal cutting by automatically changing the supply of cutting oil, mist and air in accordance with a cutting method.

This cutting device to cut a work W by directing a saw blade 4 wrapped around a driving wheel 6 and a driven wheel 7 vertically downward by slidably guiding it by inserts 10, 11 free to slide has a cutting method selection part 20D to select one of a cutting oil cutting method, a mist cutting method and a dry cutting method and a hydraulic/air pressure circuit control part 20E to control a hydraulic/air pressure circuit 19 so as to supply the cutting oil (s), the mist (m) or air (a) in accordance with the cutting method selected by the cutting method selection part 20D.