question: Due to the negative psychological consequences of the COVID-19 pandemic worldwide, it is necessary to study the factors that improve mental health. In this study, we evaluated changing income, self-restraint, fear of COVID-19, depression, anxiety, stress, and ego-resiliency, to investigate the main and moderating effects of ego-resiliency on psychological distress. We analyzed 222 Japanese samples from the dataset of Primary Survey in Japan (PSJ) in the Resilience to COVid-19 in Each Region (RE-COVER) project. The results showed significant main effects of ego-resiliency on depression and stress, and a significant interaction effect of self-restraint and ego-resiliency on depression. We also tested the significance of the moderating effect of ego-resiliency on the relationship between self-restraint and depression. The simple slope of ego-resiliency was only significant for individuals with high self-restraint. Our findings provide empirical evidence on mental health associated with the COVID-19 pandemic among the Japanese population, proving that ego-resiliency functioned to cope with the specific stresses associated with COVID-19.