This paper proposes the empirical correction of the correlated k-distribution method, to calculate the radiative heating rate in the 15 μm CO₂ band. The transmittances produced by the correlated k-distribution method in CO₂ 15 μm band are systematically displaced from the exact transmittances obtained by the line-by-line method. When the empirical corrections are applied to the correlated k-distribution transmittances, the resultant heating rates of clear-sky are significantly improved in accuracy. In addition, this empirical correction is computationally efficient. Thus the method is promising for practical purposes, such as a radiation scheme in a dynamical model.