To provide a constant flow involving no pulsating flow with respect to an analyzing apparatus by a low-priced, small-sized system.

The liquid feeding system comprises a pump 10 for pumping fluid from a storage container 12, a pulsation attenuator 28 in fluid communication with the pump and attenuating the pulsation of the fluid, and a volume sensor 52 for detecting the volume in a plenum chamber 40 receiving the fluid from the attenuator. The volume detecting sensor operates the pump 10 when the level in the plenum chamber 40 drops below a specific level, and stops the pump 10 when the level in the plenum chamber 40 is over a specific level. The pressure in the plenum chamber 40 is adjusted by a pressure head 51 connected to a pressure source.