Abstract: A safety needle cap for enclosing a needle assembly of a syringe therein includes a tubular cap body having opposite open end and closed end. The cap body is internally provided near the open end with a plurality of radially inward protruded ribs, and is formed on one side with a slit extended from the open end in a length direction of the cap body, so that the needle assembly can be set in the cap body via the slit in a cross sectional direction of the needle assembly. Therefore, a user is protected against stabbing by a sharp tip of the needle assembly. A length of the slit near the open end of the cap body has two outward expanded lateral edges to provide a flared cross section thereat, enabling the needle assembly to be more easily set in the safety needle cap via the slit.