[Problem] Because the knife edge of medical knives such as straight knives manufactured with austenite stainless steel is thin and sharp, there is the problem that the knife edge bends too easily when making incisions in the cornea, sclera, etc. during ophthalmologic surgery. The invention provides a medical knife capable of increasing the strength of the thin, sharp knife edge and preventing the reduction of sharpness. [Solution] This medical knife has a flat cutting part and an inclined surface formed along the border of said cutting part. By electrolytic polishing or chemical polishing of the inclined surface, a convexly curved cutting edge is formed on at least the edge of the inclined surface of the knife. The knife edge has a rounded configuration. The knife edge being rounded increases the thickness of the knife edge, increases the strength thereof and hinders bending.