The principal objective of this study was to determine the effects of service quality in a Korean restaurant in a Five Star Hotel in Metropolitan city causes on customers satisfaction, revisiting intentions and word of mouth communication. As a component of the study, 344 customers who had visited restaurants at 4 hotels were selected for our Q&A research, Our investigation was conducted largely frequency analysis, reliability analysis, factor analysis, and multiple regression analysis. First, as one of our study results, factors causing effects in service quality can be categorized into human service factors, physical service factors, and menu service factors. Second, the service quality of Korean restaurants has been found to exert effects on customer satisfaction, revisiting intentions, and word-of-mouth communication. Third, customer satisfaction has been determined to exert significant effects on revisiting intentions and word of mouth communication. Fourth, customer revisiting intentions has been found have been shown to exert significant effects on word-of-mouth communication. As one of the limits of this study, some difficulties did occur when attempting to implement Q&A research on customers who enjoyed restaurant services, as there was not sufficient space to interview them. As another limit, this study was conducted only with test subjects who had visited Korean restaurants in Five Star Hotels the results of our study cannot, then, be considered represent active of all Korean restaurants. Consistent with this future studies will need to be conducted not only with Korean restaurants, but also with Japanese, Chinese, and Western restaurants.