New emission bands called the M , N 1 , N 2 and N 3 bands have been found near the band edge in CuCl single crystal with excitation by the two-photon absorption of a Q -switched ruby laser. All emission intensities show non-linear dependences upon the excitation intensity. One of them, the M band located at λ3919 A at 4.2°K, is concluded as the radiative decay of a free excitonic molecule. The shape variation and peak shift to the low energy side of the M emission band with respect to the increase of the laser power are similar to those due to the raising of temperature. The line shape is an inverted replica of the Maxwell distribution. The system of the excitonic molecule has been concluded to have the effective temperature which is higher than the lattice temperature in the high density state of excitonic molecule. The mechanism of the radiative decomposition of the excitonic molecule has been discussed.