Neonatal pertussis has the potential for severe complications, even death. Mothers have been identified as the most frequent source of neonatal pertussis. Almost a dozen countries have implemented pertussis vaccination programs for pregnant women to protect neonates, but Japan has not yet done so. The aim of this questionnaire-based study was to ascertain the willingness of women to be vaccinated during pregnancy and the factors associated with willingness. Subjects were 977 pregnant women who visited either of two selected hospitals for maternity health checks. Most of the women were in their first pregnancy (96%) and about half considered a physician to be the most reliable source of information about vaccination (481/977, 49%). “Willingness to receive pertussis vaccination” was significantly associated with the factors “no fear of receiving vaccination” (odds ratio [OR]=3.10, 95% confidence interval [CI]: 2.21–4.34), “necessary to prevent pertussis” (OR=8.70, 95% CI: 6.17–12.28), “effective in pregnancy”(OR=5.46, 95% CI: 3.94–7.56), and “no concern about side effects after vaccination”(OR=3.03, 95% CI: 1.66–5.55). Pregnant women are likely to consider vaccination if they have a good understanding of the disease and its outcomes. Physicians are well positioned to improve knowledge and attitudes toward pertussis vaccination during pregnancy.