The relationship between the socioeconomic status, including the health insurance status, and prognosis of heart failure (HF) has been recognized as an important concept for stratifying the risk in HF patients and is gaining increasing attention worldwide even in countries with a universal healthcare system. However, the impact of the Japanese health insurance status on outcomes among patients admitted for acute HF has not been fully clarified. We enrolled 771 patients admitted for acute HF between January 2018 and December 2019 and collected data on the in-hospital mortality, length of the hospital stay, and cardiac events, defined as cardiovascular death and readmission for HF within 1 year after discharge. Patients were divided into two groups according to their insurance status, i.e., public assistance (n = 87) vs. other insurance (n = 684). The public assistance group was significantly younger and had a higher rate of diabetes, smoking, ischemic and hypertensive heart disease, and low estimated glomerular filtration rate (all P < 0.05). Pharmacological/invasive heart failure therapy, in-hospital mortality, and the 90-day cardiac event rate after discharge did not differ between the groups. However, the public assistance group had a significantly higher 1-year cardiac event rate than the other insurance groups (P = 0.025). After adjusting for covariates, public assistance was independently associated with the 1-year cardiac event rate (HR: 2.15, 95% CI: 1.42–3.26, P < 0.001). Acute HF patients covered by public assistance received the same quality of medical care, including invasive therapy. As a result, no health disparities were found in terms of the in-hospital mortality and 90-day cardiac event rate, unlike overseas surveys. Nevertheless, HF patients with public assistance had a higher risk for the long-term prognosis than those with other insurance. Comprehensive HF management is required post-discharge.