Emission spectroscopy of non-equilibrium Ar plasmas at atmospheric pressure has been performed on the basis of both continuous and line spectra. Unlike conventional methods, the mean squared logarithmic error (MSLE) of the experimental and estimated values of the continuous and line spectra, respectively, were added together with a weight w to find the electron temperature and density that minimize the MSLE, and the gamma value of the generalized electron energy distribution function(EEDF), under the assumption of a two-temperature generalized EEDF. The MSLE of the line spectrum is on average about 100 times larger than that of the continuum spectrum, and w=10^{-4}-10^{-3} is considered to be in the range where reasonable estimation results can be obtained.