The electron quenching rate of KrF* in an electron beam pumped laser has been studied by accurately measuring the saturation intensity in a mixture of Ar/Kr/F₂=94/6/0.284. The input intensity of the measurements was widely varied from 100 W cm^-2 (small signal region) to 100 MW cm^-2 (absorption dominant region) in order to separate laser parameters which are small signal gain coefficient, absorption coefficient, and saturation intensity from the measured net gain coefficients. The gas pressure and the pump rate were varied in the range of 0.5 to 2.5 atm and 0.3 to 1.4 MW cm^-3, respectively. The electron quenching rate constant of 4.5×10^-7 cm3s^-1 was obtained from the pressure and the pump rate dependence of the KrF* saturation intensity with the temperature dependence of the rate gas 3-body quenching rate as a function of gas temperature to the -3rd power. The small signal gain coefficients calculated with the determined quenching rate constants shows excellent agreement with the measurements.