The photodissociation mechanism and dynamics of the title molecule have been studied at excitation wavelengths of 157 and 193 nm by using a photofragmentation translational spectroscopy. In the case of the excitation at 157 nm, the C-Cl and C-Br bond ruptures occur competitively with the branching ratio of 1.0:0.3, indicating the preferential C-Cl bond rupture over the weaker C-Br bond. The C-Br bond rupture occurred via two pathways; the dissociation on the excited repulsive potential energy surface and the dissociation of the vibrationally excited molecule in the ground electronic state following the internal conversion. In the case of 193 nm, only the C-Br bond rupture on the repulsive potential energy surface was observed.