Sensitivity of azide polymer was found to be improved by addition of both Nphenylthioacridone (TA) and erythrosine (ES). The mixed sensitization effect by both sensitizers was investigated by product analysis of liquid chromatography. It is clarified that both ES and TA in the sensitization of azides are decomposed only by excitation of ES, while ES is stable to light in single addition of ES to azides. The decomposed products of ES and TA were identified as oxidized ES and N-phenylacridone (PA) respectivery. The sensitization scheme of azides by both sensitizers was made clear by the product analysis.