To improve efficiency in washing work by enabling the quantity of water to be discharged to be set in a single-lever mixing faucet.

Under a distal end portion of a discharging path 4 of a single-lever mixing faucet, a valve controller 1 is mounted to adjust the quantity of water to be discharged. A scale is provided on a handle 2 of the valve controller 1, so that the quantity of water to be discharged can be visually confirmed. During washing work, the scale on the handle 2 is confirmed beforehand, or after lever operation, the scale on the handle 2 is speedily set to a target value and washing work or the like is performed. Thus, during washing work, an accurate quantity of water to be discharged can be obtained without spending much time and efforts for fine adjustment of the lever, thereby improving work efficiency.