The research objectives were to: 1) study the level of staff service quality of KK PoonsubWatsadukorsang Co., Ltd., and 2) compare the level of customers’ opinion on the service quality of the companystaff classified by personal factors. The sample group was 227 customers who got the services of the staff and was processed throughmulti-stage random sampling. The research tool was a questionnaire. The statistics for analyzing the data included percentage, mean, and standard deviation. The hypothesis was tested through one-way analysis of variance, and compared the differences in pairs by LSD method. The statistical significance was set at the 0.05 level. The research results showed that: 1) the overall of service quality of KK PhoonsubWatsadukorsang Co., Ltd. staff was at a good level. The aspect with the highest mean was reliability, followed by attention, giving confidence, customer response and the concrete aspect of the service, and 2)in comparing the customers’ opinions on the service quality of thestaff classified by personal factors, it was found that the customers with different gender, age, education level, occupation and average monthly income, had the level of opinion toward the staff service qualityas a whole with no difference at statistically significant level of 0.05.