It had been reported that lead alloying causes the disappearance of PD in Ge-S films. However, it was confirmed that LESR continues to exist in spite of the disappearance of the PD. For Ge-S films without lead, the LESR was observed by irradiation, the intensity of which is not so strong as that giving rise to the PD. It also turned out that the density of defects, including neutral and charged ones at room temperature, remains constant after strong irradiation at low temperature. From these results, it has become apparent that in Ge-S system the PD does not originate from bond-breaking.