A nationwide questionnaire survey about community-acquired infection of coronavirus disease 2019 (COVID-19) was conducted in July 2020 to identify the characteristics of and measures taken by Japanese medical facilities providing maternity services. A case-control study was conducted by including medical facilities with (Cases) and without (Control) community-acquired infection of COVID-19. Responses from 711 hospitals and 707 private clinics were assessed (72% of all hospital and 59% all private clinics provided maternity service in Japan). Seventy-five COVID-19-positive pregnant women were treated in 52 facilities. Community-acquired infection was reported in 4.1% of the facilities. Of these, 95% occurred in the hospital. Nine patients developed a community-acquired infection in the maternity ward or obstetric department. Variables that associated with community-acquired infection of COVID-19 (adjusted odds ratio [95% confidence interval]) were found to be state of emergency prefecture (4.93 [2.17-11.16]), PCR test for SARS-CoV-2 on admission (2.88 [1.59-5.24]), and facility that cannot treat COVID-19 positive patients (0.34 [0.14-0.82]). In conclusion, community-acquired infection is likely to occur in large hospitals that treat a higher number of patients than private clinics do, regardless of the preventive measures used.