A needleless syringe comprising: a body formed in a hollow shape; a solenoid coil wound around an outer circumferential surface of the body; a cylinder coupled to the body to be in communication with an open front surface of the body and including a drug accommodating portion for accommodating a drug, and a nozzle portion for discharging the drug accommodated in the drug accommodating portion to a front; a moving magnetic body, which is inserted into the body in a longitudinal direction and moves forward by a magnetic force generated when a current is applied to the solenoid coil; a piston, which is inserted in front of the moving magnetic body inside the body and is provided to penetrate the body and the cylinder, and moves forward by an impact force applied by the moving magnetic body when the moving magnetic body moves forward, to pressurize the drug in the drug accommodating portion toward the nozzle portion; a nozzle portion opening/closing valve, which is provided to open and close a passage hole between the nozzle portion and the drug accommodating portion, is pushed by a fluidic pressure applied by the drug from the drug accommodating portion when the piston moves forward, to open the passage hole, and when the fluidic pressure is released, the nozzle portion opening/closing valve is elastically restored to close the passage hole; and a forward/backward driving unit repeating forward and backward movement of the piston by repeating the supply and cut off of a current to the solenoid coil at a preset period, wherein the forward/backward driving unit comprises: a current supply unit which is configured to repeatedly supply a current to the solenoid coil to move the moving magnetic body forward and thereby move the piston forward, and an elastic member for the piston, which applies an elastic force to the piston in a direction in which the piston moves backward when the supply of current of the current supply unit is cut off, characterized in that the current supply unit is configured to cut off the current after applying the current to the solenoid coil for a first preset time, and a mass of the moving magnetic body is 100 g or less, and the first preset time is set to 250 ms or less. a body formed in a hollow shape; a solenoid coil wound around an outer circumferential surface of the body; a cylinder coupled to the body to be in communication with an open front surface of the body and including a drug accommodating portion for accommodating a drug, and a nozzle portion for discharging the drug accommodated in the drug accommodating portion to a front; a moving magnetic body, which is inserted into the body in a longitudinal direction and moves forward by a magnetic force generated when a current is applied to the solenoid coil; a piston, which is inserted in front of the moving magnetic body inside the body and is provided to penetrate the body and the cylinder, and moves forward by an impact force applied by the moving magnetic body when the moving magnetic body moves forward, to pressurize the drug in the drug accommodating portion toward the nozzle portion; a nozzle portion opening/closing valve, which is provided to open and close a passage hole between the nozzle portion and the drug accommodating portion, is pushed by a fluidic pressure applied by the drug from the drug accommodating portion when the piston moves forward, to open the passage hole, and when the fluidic pressure is released, the nozzle portion opening/closing valve is elastically restored to close the passage hole; and a forward/backward driving unit repeating forward and backward movement of the piston by repeating the supply and cut off of a current to the solenoid coil at a preset period, wherein the forward/backward driving unit comprises: a current supply unit which is configured to repeatedly supply a current to the solenoid coil to move the moving magnetic body forward and thereby move the piston forward, and an elastic member for the piston, which applies an elastic force to the piston in a direction in which the piston moves backward when the supply of current of the current supply unit is cut off, characterized in that the current supply unit is configured to cut off the current after applying the current to the solenoid coil for a first preset time, and a mass of the moving magnetic body is 100 g or less, and the first preset time is set to 250 ms or less. a current supply unit which is configured to repeatedly supply a current to the solenoid coil to move the moving magnetic body forward and thereby move the piston forward, and an elastic member for the piston, which applies an elastic force to the piston in a direction in which the piston moves backward when the supply of current of the current supply unit is cut off, characterized in that the current supply unit is configured to cut off the current after applying the current to the solenoid coil for a first preset time, and a mass of the moving magnetic body is 100 g or less, and the first preset time is set to 250 ms or less.