The present invention relates to a device for injecting a liquid medicine such as a Ringer's solution, and more particularly, to a device for regulating the amount of liquid medicine to be injected. According to the present invention, there is provided with a device for regulating the flow rate of a liquid medicine on a flow path of the liquid medicine, comprising an inflow passage for allowing the liquid medicine to be introduced therethrough； a discharge passage for allowing the liquid medicine to be discharged therethrough； a space for storing the liquid medicine introduced through the inflow passage therein； a capillary unit placed between the space and the discharge passage and having at least two capillaries and a plurality of outlets formed on the side of the discharge passage to correspond to the respective capillaries； and a discharge amount regulating valve that is placed between the capillary unit and the discharge passage and is movable to change the number of capillaries communicating with the discharge passage.
