The present invention provides a safety syringe which resolves a problem in the prior art whereby the needle assembly does not engage the plunger properly due to limitations in the syringe protrusion molding. The syringe of the present invention comprises: a cylinder which has a space therein to contain fluid and forms a fluid discharging portion at one end a plunger which is inserted inside the cylinder and slid in a longitudinal direction a piston which is associated with the upper portion of the plunger in order to make airtight contact between the plunger and the cylinder a syringe needle assembly which is equipped at the upper portion of the cylinder and affixes a syringe needle. The syringe needle assembly is inserted into and contained inside the cylinder after use and is then disposed. In the needle assembly, plural needle supports comprising a first connector and a second connector are extended to the lower portion. The plunger has a needle support insertion member at the upper portion so that it cannot be separated after the needle supports of the needle assembly are inserted. When the plunger is retracted, the needle assembly is retracted and contained in the cylinder. In the needle support insertion member, a ring-shaped protrusion is placed at the upper portion, and plural ring-shaped protrusion supports which connect and support the ring-shaped protrusions are formed.
