There is described a disposable syringe comprising: a syringe body, substantially comprising a hollow cylinder (1) with a plunger (2) -inserted therein, the plunger being hollow and closed at the end portion which is external to the cylinder, and a first plug (3) inserted in the plunger (2) end portion which is internal to the cylinder； -a needle body (4), substantially comprising a needle (5) having a pre-loaded spring (6) around the head (5') and a second plug (7) around the head of the needle, said spring determining the permanent introduction of said needle (5, 5') within said plunger (2) after use.
