The application and clinical impact of rapid antigen detection test (RADT) in the treatment of acute pharyngitis is unknown in Japan. We aimed to examine the proportions of RADT usage to identify Group A β-hemolytic Streptococcus (GAS) in outpatients with acute pharyngitis and evaluate the association between RADT and antibiotic treatment. We analyzed health insurance claims data from 2013 to 2015. Logistic regression models were used to analyze associated factors with RADT, overall antibiotic prescription, or penicillin use. We analyzed 1.27 million outpatient visits with acute pharyngitis, in which antibiotics were prescribed in 59.3% of visits. Of the total visits, 5.6% of patients received RADT, and 10.8% of the antibiotics were penicillin. Penicillin selection rates were higher in cases with RADT (25.4%) than those without RADT (9.7%). Compared to large-scale facilities, antibiotic prescription rates were higher in physicians' offices. For factor analysis, age (3-15 years), diagnosis code (streptococcal pharyngitis), size of the medical facility (large-scale hospitals), and physician's specialty (pediatrics) were associated with RADT use. Penicillin selection rate increased with RADT implementation (25.4% vs. 9.7%: adjusted odds ratio 1.55; 95% CI, 1.50-1.60). At 63% of the facilities, the RADT implementation rate was <5% of acute pharyngitis visits prescribed antibiotics. In conclusion, the proportion of RADT usage for outpatients with acute pharyngitis was low in Japan. With appropriate indication and evaluation, we expect that more utilization of RADT can help promote antimicrobial stewardship for outpatients with acute pharyngitis by prompting penicillin therapy. Further investigation with detailed clinical data are warranted.