Objective This study aimed to evaluate the influence of public assistance on patients with out-of-hospital cardiac arrest (OHCA) who received extracorporeal cardiopulmonary resuscitation (ECPR) in Japan. Methods We conducted a secondary analysis of data from the SAVE-J II study, a retrospective, multicenter registry study involving 36 participating institutions in Japan. Patients with cardiac arrest who received ECPR were divided into two groups, depending on whether or not they had received public assistance. The primary outcome was 30-day survival. Secondary outcomes were as follows: 30-day favorable neurological outcomes (Cerebral Performance Category scores 1-2); survival at discharge; favorable neurological outcome at discharge; number of Intensive Care Unit (ICU), hospital, ventilator, and extracorporeal membrane oxygenation (ECMO) days; medical expenses; proportion of percutaneous coronary intervention (PCI); target temperature management (TTM); mechanical circulatory support (MCS) device use; and withdrawal of life-sustaining therapy (WLST). Results Of the 2,157 patients registered in the SAVE-J II study, 1,885 were enrolled in this study; 99 patients (5.3%) received public assistance, and 1,786 patients (94.7%) did not. Multivariable logistic regression analysis did not show a significant difference in 30-day survival (OR: 1.22; 95% CI: 0.77-1.95; p = 0.40). Except for the use of MCS devices, there were no significant differences in secondary outcomes. Conclusion The use of public assistance was not associated with clinical outcomes or treatment options, except for MCS devices, among OHCA patients receiving ECPR. These results may imply that clinicians do not need to hesitate in implementing ECPR for OHCA patients receiving public assistance. Further studies on the association between socioeconomic status and ECPR are warranted.