This research investigated the factors that effect on the trust and loyalty in on-line shopping mall and analyzed a structural relationship of these variables. The variables are service quality, information quality of on-line WOM(afternote), reputation of on-line shopping mall. The Instrument dimensions of service quality are tangibles, responsiveness, assurance, diversity goods and price fairness. The Instrument dimensions of information quality of on-line WOM(afternote) are usefulness, abundance, accuracy and specialty. The Instrument dimensions of reputation of on-line shopping mall are cognizance and comment. The results by LISREL are as follows : There are 7 factors that effects on trust and loyalty. These are tangibles, responsiveness, assurance and price fairness of instrument dimensions of service quality, usefulness, specialty of instrument dimensions of information quality of on-line WOM, cognizance of the Instrument dimensions of reputation of on-line shopping mall. Specially, there are significant point that usefulness and specialty of afternote which can contact easily in on-line shopping mall effect on the trust and loyalty in on-line shopping mall.