The present invention provides a semiautomatic syringe with improved safety including: a main body; a receptacle which is installed at one side of the main body, receives therein a set amount of infusion solution, and has a set pressure; an infusion solution tube which extends by a set length while penetrating the main body, connects with the receptacle, and provides a passageway for moving the infusion solution; a protective cover which is installed at the other side of the main body, connects with the infusion solution tube, extends by a set length, and has a hollow portion; an injection needle which is provided in the protective cover and has an injection hole formed to discharge the infusion solution, which moves through the infusion solution tube, to the outside; and a flow rate adjusting member which is installed in the main body and adjusts a movement amount of the infusion solution by opening and closing the passageway of the infusion solution tube, in which the injection needle is provided in a state of being inserted into the hollow portion of the protective cover, and a part of the injection needle protrudes to the outside of the protective cover by a change in pressure in the receptacle when the passageway of the infusion solution tube is opened, thereby achieving a more convenient, economic, and safe usage.