Using the Wang-Landau Monte Carlo method, we evaluate the partition function zeros in the complex temperature (y = e^-2J/kBT) plane for the L × L square-lattice Ising models (L = 4 ~ 20). We find the first zeros which are the closest to the positive real axis and the most important in determining the critical point and the critical exponents of the Ising model. The values of the first zeros, produced through Monte Carlo simulations, are in excellent agreement with the exact ones. The estimated values of 0:4209(78) for the critical point and 0:992(55) for the thermal scaling exponent are obtained from Monte Carlo data. These estimated values are in excellent agreement (about 1 % errors) with the exact ones.