A threshold photoelectron spectrum and its component spectra of Auger cascades after Ar K-shell photoionization have been measured by coincidences between threshold photoelectrons and residual ions of the cascades. These spectra exhibit remarkable profiles of post-collision interaction effects due to the Auger cascades. The peak shift increases gradually according to the times of interactions, but the peak broadening is almost independent of the times of interactions. These profiles are analysed in terms of a simple model expressing the probability of Auger electron emissions by statistical weights.