To provide a charge quantity controller of a dispersed droplet, which controls the quantity of a charge conveyed by droplets jetted out of an injection nozzle.

A charge quantity controller of a dispersed droplet includes: a metal injection nozzle; an insulating joint which is formed of an insulating material and which is connected between the nozzle and a pipe supplying a cleaning liquid to the nozzle; an electric wire stretched between the nozzle and the ground; an ammeter attached in the middle of the wire; and a carbon dioxide dissolving device which is attached in the middle of the pipe and which dissolves carbon dioxide in the cleaning liquid. The quantity of the carbon dioxide supplied to the carbon dioxide dissolving device is controlled on the basis of a current value of the ammeter.