Abstract: A sharpener for the knife blade of a slicing machine wherein the cutting edge of the knife blade is of involute shape. The mechanism comprises a pinion which is coaxially securable to the knife blade drive shaft, an elongate member is driving connection with the pinion and a sharpening mechanism mounted on the elongate member. The elongate member is moved pivotally and longitudinally with respect to the pinion whereby the sharpening mechanism follows the involute contour of the knife blade cutting edge during the sharpening procedure. To avoid unwanted movements of the sharpening mechanism the elongate member and pinion are mounted on a support means which includes an arm extending in the same longitudinal direction as the elongate member, and a slide block is slidably mounted on the arm and carries therewith the elongate member and the sharpening mechanism.