A potentiometric titration method for conducting titration based on an amount of a titrant added and an indicator potential, said method comprising: assuming a continuous line prepared by plotting a value of the indicator potential on an ordinate axis and plotting a value of a volume of the titrant on an abscissa axis, as a titration curve, the values being determined according to the titration procedure; assuming a continuous line prepared by plotting an absolute value of a rate of change in potential on an ordinate axis and plotting the value of a volume of the titrant on an abscissa axis, as a differential curve; assuming a value on the titration curve which corresponds to a peak on the differential curve, as a tentative terminal point; computing a straight line connecting two measured values on the titration curve which are present adjacent to the tentative terminal point; computing a linear first estimation line by a least squares method based on measured values (d1, d2, d3) on the titration curve which are present in the range of tentative terminal point - number of decision points to tentative terminal point - number of decision points + 2; computing a linear second estimation line by a least squares method based on measured values, and on the titration curve which are present in the range of tentative terminal point + number of decision points - 2 to tentative terminal point + number of decision points, computing an intermediate line spaced an equal distance apart from each of the first estimation line and the second estimation line; and computing an intersection point of the intermediate line and the straight line to read out a value of the intersection point on the abscissa axis as a terminal point (a) of the titration; wherein: the number of decision points represents the number of the measured values on portions of the titration curve previously set and used for determination of a terminal point of the titration; and the number of the measured values are not less than 3 in each of the portions of the titration curve which extend in positive and negative directions, respectively, along the abscissa axis, on the basis of the tentative terminal point as a reference point. assuming a continuous line prepared by plotting a value of the indicator potential on an ordinate axis and plotting a value of a volume of the titrant on an abscissa axis, as a titration curve, the values being determined according to the titration procedure; assuming a continuous line prepared by plotting an absolute value of a rate of change in potential on an ordinate axis and plotting the value of a volume of the titrant on an abscissa axis, as a differential curve; assuming a value on the titration curve which corresponds to a peak on the differential curve, as a tentative terminal point; computing a straight line connecting two measured values on the titration curve which are present adjacent to the tentative terminal point; computing a linear first estimation line by a least squares method based on measured values (d1, d2, d3) on the titration curve which are present in the range of tentative terminal point - number of decision points to tentative terminal point - number of decision points + 2; computing a linear second estimation line by a least squares method based on measured values, and on the titration curve which are present in the range of tentative terminal point + number of decision points - 2 to tentative terminal point + number of decision points, computing an intermediate line spaced an equal distance apart from each of the first estimation line and the second estimation line; and computing an intersection point of the intermediate line and the straight line to read out a value of the intersection point on the abscissa axis as a terminal point (a) of the titration; wherein: the number of decision points represents the number of the measured values on portions of the titration curve previously set and used for determination of a terminal point of the titration; and the number of the measured values are not less than 3 in each of the portions of the titration curve which extend in positive and negative directions, respectively, along the abscissa axis, on the basis of the tentative terminal point as a reference point. the number of decision points represents the number of the measured values on portions of the titration curve previously set and used for determination of a terminal point of the titration; and the number of the measured values are not less than 3 in each of the portions of the titration curve which extend in positive and negative directions, respectively, along the abscissa axis, on the basis of the tentative terminal point as a reference point.