Disclosed herein is a device for quantitatively supplying a liquid in a plasma sterilization system. The device includes a quantitative cylinder, a quantitative piston and a quantitative basket. The quantitative cylinder includes a quantitative inlet pipe, which is configured such that the outlet of a liquid container is inserted thereinto, and a liquid in the liquid container is vertically supplied to the quantitative cylinder, and a quantitative outlet pipe, which is configured such that the liquid is vertically drained from the quantitative cylinder. The quantitative piston is configured to rectilinearly reciprocate in the quantitative cylinder, and is provided with a quantitative transfer depression, which is formed in the leading end thereof to a predetermined depth. The quantitative basket is configured to quantitatively receive the liquid according to the rectilinear reciprocation of the quantitative piston.
