The present invention provides a developing process including the steps of charging toner particles supported on a developer carrier; and providing the charged toner particles to an electrostatic latent image formed on an image carrier, wherein, the charged toner particles satisfy formulas (1) and (2) shown below, when being measured by the laser doppler method in an oscillation field in an acoustic alleviation cell to determine individual particle size and charged amount thereof: k1=(B2-B1)/(A1-A2)<2/3 (1) B2<0 (2) wherein A1 [.mu.m] and B1 [fC] represent the particle size and the charged amount of the charged toner particle in the division that has the largest number proportion in the distribution divided by the measured particle size and the measured charged amount, respectively; A2 [.mu.m] represents the particle size in the division that has the smallest particle size in the particle size distribution, provided that the number proportion of the division is 1% or more; and B2 [fC] represents the charged amount in the division that has the largest number proportion along the particle size divisions of A2.