The ozone generation by negative corona discharge in coaxial cylindrical system of electrodes have been studied experimentally in Ar+O2 and N2+O2 mixtures. Both in argon and nitrogen mixtures with oxygen the monotonous decrease in ozone concentration [O3] was observed at decreasing oxygen content in mixtures and the constant input energy density η. The rate coefficients for the ozone generation and ozone decomposition were obtained by fitting experimentally measured data [O3]= f(η) with Vasiljev-Eremin formula. The calculated rate coefficient for ozone generation in N2+O2 mixtures at low content of oxygen (below 20%) was found considerably higher than that in Ar+O2 mixtures. Increase in the rate coefficients for ozone generation and decomposition was observed with decreasing content of oxygen in both mixtures. The experimental results are in qualitative agreement with the simple model incorporating five main chemical processes in mechanism of ozone generation.