In order to follow global modernization in food industry, Raku Japanese Restaurant Medan changed their restaurant’s management system, including service performance. For this reason, writer was interested to learn how the service quality toward customer satisfaction in Raku Japanese Restaurant Medan is. This quantitative research aimed to find out how were the partial effect and simultaneous effect of tangibility (X1), reliability (X2), responsiveness (X3),assurance (X4), and empathy (X5) (service quality dimension) toward customer satisfaction (Y). This study also aimed to analyze which variable of service quality has the most dominant influence on customer satisfaction.The data was collected by distributing questionnaire using four-option Likert scale to 100 respondents. The data analysis method used in this study was multiple linear regression analysis, classical assumption test, F test, and t test. The results of the F-test analysis concluded that the dimensions of service quality which consists of tangibility, reliability, responsiveness, assurance, and empathy had a positive simultaneous significant effect toward customer satisfaction. The ttest analysis result concluded that there are a partial and significant positive influence of tangibility, reliability, responsiveness, assurance, and empathy towards customer satisfaction at Raku Japanese Restaurant Medan. The most dominant service quality dimension variables that influence the most is responsiveness variable. The result of multiple linear regressions is as follows: Y = 1.718 + 0.192 X1 + 0.107 X2 + 0.216 X3 + 0.107 X4 + 0.284 X5. The dimensions of service quality give 55.9% contribution in influencing customer satisfaction at Raku Japanese Restaurant Medan.