To provide a water supply quantity controlling system of a self power feeding type, controlling and effectively using city water (agricultural water or the like) even in a place where it is difficult to secure commercial power source.

This water supply quantity controlling system has noncommercial power sources 20 and 30 such as a solar light power generator and a hydroelectric power generator, an electric valve 60 which is driven with the noncommercial power sources 20 and 30 and controls water supply, a noncontact card 48 of union members, a reader 46, a controller 42 which controls the electric valve 60, and a stop switch 44 which stops water supply. It is possible to control a water demand condition and plan equipment arrangement through setting in the system an antenna 50 which records water supply data of union members and sends the water supply data of union members to a central observation post set with data collection equipment to collect data, and as a result to effectively use agricultural water.