PURPOSE: To obtain an automated and miniaturized pH analyzing system for nuclear power stations which is reduced in radiation exposure by reducing the amount of secondary waste water.

CONSTITUTION: The title analyzing system is provided with a sample container 1 for containing analysis samples, micro-sample pump 2 which sucks in the sample from the container 1, sample cell 7 connected to the outlet of the pump 2 through a first channel change-over valve 3, and pH electrode 8 attached to the cell 7. In addition, the analyzing system is also provided with an amplifier 9 which amplifies the electric signal of the electrode 8, pH indicator 10 connected to the amplifier 9, second channel change-over valve 4 which is connected to the upstream side of the valve 3 and switches two kinds of pH standard solutions to each other, and sequencer 11 which controls the valves 3 and 4, pump 2, and amplifier 9.