This study examined the effect of the trust of a restaurant brand on the quality of brand relations centered on the mediating effect of brand promise. The survey was conducted on September 18, 2018 to October 2, 2018, with a total of 707 end users, who are under the age of 19~59, using the restaurant brand for the last six months. The panel survey was conducted by distributing a questionnaire address (URL) email through an online questionnaire. As a result, if you apply the parameters of brand commitment between brand trust and brand relationship quality, brand promise an important role and influence. In particular, only one of the three elements of differentiation, consistency and continue, which are sub-dimensions of brand promise, was continue. This means that consistently long term continue are paramount between brand trust and the quality of brand relationships. These results can be applied to the brand marketing and operations of catering companies.