The Vacuum Retractable Safety Syringe (VRS) 100 for singe use comprises a plunger barrel assembly 114, outermost barrel 102 and a needle carrier assembly 104 holding a detachable needle 140 along with needle cover 142. The plunger barrel assembly comprises an inner and an outer plunger barrels. The outer plunger barrel 112 is provided with two diametrically opposite longitudinal slots 172 & 173 holding conical notches 145 &146 of finger locks 143 & 144, provided at the distal end of the inner plunger barrel. The inner plunger barrel housing inside the outer plunger barrel is also provided with a second piston seal 150 at proximal end. The outer plunger barrel 112 opening at proximal end is provided with a first piston seal 170 at the outer surface. The plunger plug 110 provided with a centrally positioned furrowed knob 154 at proximal surface is fixedly mounted at the proximal end of the outer plunger barrel. The finger lock 166 is provided at the distal end of outer plunger barrel to prevent the removal of plunger assembly from the outermost barrel. The outer most barrel comprises a uniformly elongated hollow cylindrical tubular body, provided with a conical jacket 126 opening at the proximal end, a finger rest 128 and two sets of uniform, inner circumferential C-grooves 120 and 122 at distal end. A conical needle carrier assembly 104 comprising a hollow conical needle carrier 139, holding a detachable straight hollow hypodermic needle, is fixedly mounted in the conical jacket of the outermost barrel with the help of an elastic O- ring 136. The needle carrier is provided with a cavity 130 with locking means 132 to capture the knob 154 provided in the plunger plug 1 10, which opens in a detachable straight hollow hypodermic needle 140 at proximal end. While working with the syringe, the plunger assembly 114 is pulled in backward direction until the notches 145 & 146 get engage therein the conical groove 122 to fix the inner plunger barrel. Further push of the plunger barrel in forward direction, creates a vacuum between the plunger plug 110 and inner plunger barrel 108. The medicinal dosage may be sucked into the chamber between the outermost barrel and plunger assembly as usual. As soon as the last drop of medicine is injected into the body of patient, the furrowed nipple 154 inserts and snap locks into the cavity 130 of needle carrier assembly 104 with the help of locking members 156 and 132. The plunger assembly 1 14 pushes the O-ring 134 in forward direction, to dislodge the needle carrier, consequently, the plunger plug 110 holding needle carrier along with needle gently retracts in backward direction and finally encapsulates inside the plunger barrel due to the pull of vacuum. Simultaneously, the outwardly protruded finger lock 166 snap locks within the conical groove 120 to completely lock the plunger barrel 112 inside the outermost barrel 102 to render the complete syringe assembly quite unusable for any further use.