This study aimed to show the changes in health-related quality of life (HRQoL) after a sustained virological response (SVR) to hepatitis C treatment. A retrospective study was conducted among 1,546 patients with SVR to interferon-based (IFN-based) or direct-acting antiviral (DAA) anti hepatitis C virus treatments from January 1990 to March 2017 in five hospitals. The survey was conducted between November 2017 and October 2018. A questionnaire including the Japanese version of the EQ-5D-3L before and after SVR by IFN-based or DAA treatment was used to assess changes in HRQoL retrospectively. Of the 1,546 patients who achieved SVR, 580 achieved SVR with IFN-based treatment (SVR-IFN) and 966 achieved SVR with DAA treatment (SVR-DAA). Comparison of HRQoL before and after treatment revealed a significant increase in SVR-IFN (0.9078 vs. 0.9278, p = 0.0406). For SVR-IFN, patients in their 60s and 70s showed a significant increase in HRQoL after treatment. In contrast, changes in HRQoL in SVR-DAA were not statistically significant (0.9018 vs. 0.9063, p = 0.3908). For SVR-DAA, HRQoL significantly improved for patients in their 50s and 60s. The results of this study showed a trend toward improvement or unchanged HRQoL in patients who achieved SVR, despite advanced age. The results of this study can serve as a basis for follow-up after SVR and cost-effectiveness analyses.