The present invention relates to a syringe and, particularly, to a device for more smoothly suctioning a medicinal fluid by sharing a part of an injection channel excluding a syringe needle, or by forming a suction channel completely independent from the injection channel in a conventional syringe having the injection channel including the syringe needle, the syringe comprising a syringe needle (10) and cylinder (20) so as to have an injection channel extending from the cylinder (20) to the syringe needle (10), and further comprising: an opening and closing means (400) for selectively sealing the injection channel； a suction channel including a through-hole (200) for allowing for communication between the inside and the outside of any one of the syringe needle (10), a connector for connecting the syringe needle (10) to the cylinder (20), and the cylinder (20), such that the suction channel extends up to the cylinder (20) from a hollow cap (100) having a tip； and a valve means (300) for controlling the opening and the closing of the suction channel by a user operation. Therefore, since a separate suction channel not passing through a syringe needle is formed in a conventional syringe so as to allow a medicinal fluid to suction more smoothly, user convenience and marketability of a product can be maximized, and the suction channel can be forcibly closed during injection.
