It is necessary to implement 100% smoke-free environments in all indoor workplaces and indoor public places in order to protect people from exposure to second-hand tobacco smoke (SHS). Forty-four countries have already implemented comprehensive smoke-free legislations according to the Framework Convention on Tobacco Control (FCTC) Guidelines on protection from exposure to tobacco smoke. The Occupational Safety and Health Law (OSHL) was partially revised to strengthen the countermeasures against SHS in Japan in 2014. However, the revision was only minimal. Firstly, it is necessary to make efforts to implement countermeasures against SHS (their implementations are not obligatory, as required in Article 8). Secondly, the revised OSHL allowed the implementation of designated smoking rooms inside workplaces (Article 8 requires 100% smoke-free environments). Thirdly, revised OSHL does not effectively cover the small-scale entertainment industry so that workers in restaurants and pubs will not be protected from occupational SHS. We explain the importance of implementation of 100% smoke-free environments by law, using the data on leakage of smoke from designated smoking rooms, and occupational exposure to SHS among service industry workers. The decrease in the incidence of smoking-related diseases in people where a comprehensive smoke-free law is implemented is also introduced. These data and information should be widely disseminated to policy makers, media, owners of service industries, and Japanese people.