This research suggests critical and specific decisive variables that affect general service quality of the products in family restaurants, considering features of services in which consumption and production happens simultaneous by collecting the raw data through point of sales. It also analyses the factors and helps to offer them practical strategies by providing managers of the restaurants and marketers with empirical viewpoints based on the research. Generally, family restaurants need their own physical environment and are required to encourage customers to revisit themselves by maintaining pleasant environment as well as, considering space for customers and for employees' working routes and effective maintenance of the facilities. The result of the study also tells that even if the unimportant factors did not affect much on the restaurants, management over these factors can be a differentiated strategy for competitive advantage over the other businesses.