A method for measuring liquid to be transferred from a container or containers to a measurement pot includes the steps of: determining an initial degree of opening of the valve for controlling flow-rate of the liquid from the container to the pot based on the valve's flow-rate characteristics and an arbitrarily chosen set value; opening the valve by the initial degree of opening; detecting the actual amount of liquid that has flowed into the pot; determining a next degree of opening of the valve based on the actual measurement and the set value; and changing the degree of opening of the valve to the next degree of opening. The determination of the degrees of opening of the valve is based on fuzzy control, which uses a fuzzy inference from the set value and actual measured value. An apparatus for measuring liquid for use in a liquid mixing apparatus uses the above-mentioned method.