A needleless syringe for injecting an injection objective substance into an injection target area by discharging the injection objective substance by a voltage application to a driving unit without using any injection needle comprises a protruding member which is provided movably from a first position at which a forward end thereof protrudes from an end surface of a housing to a second position at which a protruding length of the forward end from the end surface of the housing is shorter than a protruding length provided at the first position and the forward end and a discharge port can be brought in contact with the injection target area； a maintaining mechanism which maintains the protruding member at the first position before the discharge energy is generated by the driving unit； and a power source circuit which applies a voltage to the driving unit when the protruding member having been maintained at the first position is moved to the second position by means of a pressing force received by the forward end of the protruding member. Accordingly, the unintended discharge from the syringe is appropriately avoided.
