In this paper the authors presents a new method, named FR-SERVQUAL, of evaluating perceived service quality in Public Sectors, using triangle fuzzy numbers and semantic differential scale. By conventional quantification methods, it is not easy to express the notion of a linguistic variables and customers' subjective judgements. In contrast to the conventional PZB methods which express the customers' perception of quality as a function of gap between the expected and perceived service, this paper suggests to use the ratio of the two. Through an application example, this paper shows that the current FR-SERVQUAL approach provides a more realistic way of measuring service quality compared to existing methods.