PROBLEM TO BE SOLVED: To provide a measuring method of a zeta potential distribution in which deformation of a particle due to application of an electric field is suppressed and influence of Brownian motion is eliminated, and which can accurately and easily perform measuring of the zeta potential distribution of the particle.SOLUTION: A measuring method of a zeta potential distribution including following zeta potential measurement steps (i)-(iii), and a quality control method of a particle and water dispersion using the measuring method are provided. Step i): A first electric field is applied to the particle in a measurement cell, and a zeta potential distribution 1 is measured, and then normalization is performed to obtain a normalized zeta potential distribution 1. Step (ii): A second electric field whose intensity is higher than that of the first electric field is applied to the particle in the measurement cell in a range of 400-4000 V/m, and a zeta potential distribution 2 is measured, and then normaliza
