Continuous liquid feeding system and control method thereof

The purpose of the invention is that the continuous liquid feeding system can prevent interruption of liquid feeding, and can inhibit the variation of the liquid feeding amount when a pump used in the liquid feeding action is switched. The continuous liquid feeding system (50) of the invention sucks liquid contained in a container (40) and discharges to a liquid feeding destination through pressurization. The system comprises a plurality of pumps (18a, 18b) communicated with the container, valves (22a, 22b) equipped for the pumps and disposed between the pumps and the container, motors (13a, 13b) equipped for the pumps and driving the pumps, and a controller (31) controlling the motors and the valves. When one pump discharges a predetermined flow rate, the controller allows the other pumps to begin the sucking action or stop the sucking action. At a predetermined time after one pump begins to discharge, or a predetermined time before the pump stops discharging, the discharging flow rate of the pump to be disc