Disclosed is an an apparatus for forming cogs on a surgical thread, comprising: a bobbin having a suture thread wound thereonto first and second tension rolls for maintaining, at regular tensions, the suture thread unwound from the bobbin a pair of friction rolls for drawing the suture thread and allowing the suture thread to pass through so as to be discharged through an outgoing side a tension plate operating up and down, for temporarily fixing the suture thread being discharged through the outgoing side by the friction roll and a cog-forming knife for forming cogs by rotating and simultaneously moving forward toward the suture thread fixed by the tension plate and also obliquely moving to the left or the right so as to make oblique cuts on the surface of the suture thread.
