The present invention relates to a syringe and, particularly, to a device, with respect to an existing syringe that forms an injection passage including a syringe needle, which by sharing a portion of the injection passage with the exception of the syringe needle or by forming a suctioning passage completely separated from the injection passage, facilitates smoother suctioning of liquid medicine. With respect to a syringe including a syringe needle (10) and a cylinder (20) and forming an injection passage extending from the cylinder (20) to the syringe needle (10), the syringe is configured by comprising: opening/closing means (400) for selectively sealing the injection passage； a through-hole that communicates the inside and outside of any one the syringe needle (10), a connector (500) for connecting the syringe needle (10) to the cylinder (20), and the cylinder (20)； and a one-way valve means (300) for restricting the opening and closing of the through-hole, wherein the syringe further comprises a suctioning passage extending from a hollow cap (100) having a tip to the cylinder (20). By forming a separate suctioning passage that does not pass through a syringe needle on an existing syringe to facilitate smoother suctioning of liquid medicine, user convenience and product value can be maximized.
