ObjectivesHeated tobacco products (HTPs) and electronic cigarettes (e-cigarettes) are rapidly gaining popularity, especially in Japan. However, at the time of the survey (2018), there was no national legislation banning HTPs or e-cigarette use in the workplace. The objective is to examine the current situation for workplace smoke-free policies which ban the use of HTPs/e-cigarettes and the associations of such rules with the use of HTP and e-cigarette as well as conventional cigarette smoking.MethodsAn internet-based self-reported questionnaire survey was conducted in 2018 as a part of the Japan Society and New Tobacco Internet Survey study. 5646 eligible employees aged 15–72 years were analysed. Proportions and adjusted rate ratios for HTP and e-cigarette use were calculated according to covariates, using Poisson regression models. Those who reported HTP or e-cigarette use within 30 days were defined as current user of the products.ResultsIn workplaces which prohibited smoking indoors but permitted the use of HTPs/e-cigarettes, the rate ratios of HTP use was 2.19 (95% CI 1.57 to 3.06), e-cigarette use was 3.86 (95% CI 1.97 to 7.57) and combustible cigarette use was 1.67 (95% CI 1.19 to 2.34) when using workplaces which also prohibited HTPs/e-cigarettes as a reference category.ConclusionsWorkplaces that allow HTP/e-cigarette use indoors were associated with higher rate for HTP and e-cigarette users, and for combustible cigarette smokers. National legislation banning tobacco should be enforced and also cover HTPs and e-cigarettes in order to avoid renormalisation of smoking and nicotine addiction.