BACKGROUND: The trend of the diffusion of heated tobacco products (HTPs) is a great concern because HTPs have become available worldwide. This study examined the sociodemographic characteristics of HTPs users in Japan, which were first launched. METHODS: This cross-sectional study used data from an online survey conducted in 2017. A total of 4,926 participants, aged 20-69 years, were included. The dependent variable was the type of tobacco products used. The independent variables were age and equivalent income. Two analyses estimated the odds ratios (ORs) for 1) being smokers compared to "non-smokers", and 2) being "HTP smokers" compared to "only combustible cigarette smokers." Analyses were stratified by sex. Educational attainment and occupation were also used in the sensitivity analyses. RESULTS: The percentages of "non-smokers," "only combustible cigarette smokers," and "HTP smokers" were 82.8%, 14.2%, and 3.0%, respectively. When compared to the oldest participants (aged 60-69), the youngest participants (aged 20-29) tended to be "HTP smokers" (OR=7.90 (95% CI=3.09-20.22) for men and 9.28 (2.14-40.28) for women). Compared to participants with the lowest incomes (<2 million), those with the highest incomes (≥4 million) tended to use HTPs (OR=2.93 (95% CI=1.56-5.49) in men and 1.82 (0.73-4.54) in women). These trends were consistent when analyses included only smokers. There were consistent results in other SES measurements; educational attainment and occupation. CONCLUSIONS: Younger or more affluent people tended to use HTPs, although smoking rates among these populations were generally lower. New tobacco control efforts are required.