Abstract: In a motor driven circular saw, a saw blade drive is provided, by which a rotary movement of a saw blade, supported on a rotary blade shaft, is superimposed by a back and forth-movement in the direction of sawing to produce a forward stroke and a backward stroke of the blade and to thus improve cutting efficiency of the saw. The saw blade drive includes a pinion at the end of a motor shaft, a first gear meshed with the pinion and supported on the saw blade shaft, a second gear meshed with the first gear and having a cam and eccentrically positioned together with the cam on a stationary axle. A coupling rod connects the cam with the saw blade shaft to impart to the latter the back-and-forth movement.