The present invention relates to a safety cap for a disposable syringe. In particular, the safety cap for covering a needle of the syringe has a cutout insertion portion formed at one side thereof and a ball provided at the inner upper end of the cutout insertion portion, so that it is possible to couple the needle of the syringe to the safety cap by inserting the needle into the ball and then rotating the needle about the ball. Further, the safety cap has a fitting groove formed at the lower end portion thereof, so that the safety cap can be coupled to and covered on the upper portion of the used syringe through the cutout insertion portion from the lateral side of the syringe, and be then forcibly coupled to the upper portion of the syringe through the fitting groove. Therefore, the safety cap can prevent a user, after using the syringe, from having a wound by being pierced by the needle or from being infected by germs through the wound.
