The deployment of mega constellations has had a significant effect on the compounding space debris environment, increasing the number of on-orbit objects in all conditions and damaging the stability of the space debris environment. The increased density of space objects is associated with an increased risk of on-orbit collisions. Collision risk exists not only between a mega constellation and the space debris environment but also inside a mega constellation. In this study, we used the Starlink constellation to investigate the self-induced collision risk caused by malfunctioning satellites. First, we analyzed the conjunction condition between malfunctioning and operative satellites based on long-term orbital evolution characteristics. The collision probability was then calculated based on the conjunction analysis results. The results show that malfunctioning satellites in Phase 1 cause an 86.2% self-induced collision probability based on a malfunctioning rate of 1%, which is close to the collision probability caused by objects larger than 6 cm during five years of service. Therefore, self-induced collisions are another important risk factor for the Starlink constellation.