Abstract: This invention is a tool designed to sharpen rotary cutter blades used for cutting fabrics. In the preferred embodiment, when a dulled blade is placed over a threaded shank, an inside-threaded clamp is screwed down upon the blade, pressing it tightly against a platform from which the shank rises, and holding the blade from turning. When an upper casing containing an inside angled abrasive strip is lowered over the clamp until contact is made against the blade surface, the abrasive strip is brought into contact with the blade edge. When the upper casing is rotated around the tightened clamp, the abrasive acts upon the blade edge and thereby sharpens the edge. Removing the upper casing and clamp, the blade is then turned over, replaced on the platform and the process repeated, thereby sharpening both sides of the blade edge.