The infrared chemiluminescence technique has been applied to the catalytic oxidation of CO on a Pt(110)(1 x 2) surface. The vibrational and the rotational states of CO2 formed on the reconstructed Pt(110)(1 x 2) surface are more excited than those on the terrace Pt(111) surface. The vibrational state of the product CO2 strongly depends on the CO coverage : the vibrational temperature (T-V) of the product CO2 becomes higher, as the coverage of CO increases.