A flow analysis flow analysis system having a deaerator for removing gas bubbles in a liquid upstream an analysis section. The deaerator comprises a liquid-containing means variable in internal volume for containing the liquid together with gas bubbles included in the liquid; a liquid-introducing means for introducing the liquid into the liquid-containing means; a gas bubble-discharging means for discharging gas bubbles in the liquid-containing means by decreasing the internal volume of the liquid-containing means while maintaining in the liquid-containing means at least part of the liquid introduced by the liquid-introducing means; and a liquid delivery means for delivering to the analysis section the liquid in the liquid-containing means from which gas bubbles have been discharged by the gas bubble-discharging means.