National Delivery Service Industry has grown explosively in 2000s. In the background of this growth, Electronic Commerce is the major source. In 2001s, market size of electronic commerce was 118trillion won, and it is grown to almost 1,000trillion in 2012. Delivery Service is a delivery which means that is used in various areas by changing the purchasing pattern of consumer not only in electronic commerce but also in general area. In case of delivery by a third party, there was a problem between electronic commerce company and comsumer when some conflicts were occurred regarding the delivery service. At that time, the focused matter was that whether delivery service company has responsibility or not. However the social interest of the issue that how can the personal data be protected when delivery service company is dealing, has increased in these days. First of all, for delivery of goods by delivery service company in the electronic commerce, the personal data of buyer is transferred from online company to delivery service company. In this process, the personal data is used to use over the purpose of delivery or could be disclosed. Therefore, this study tries to find what is the scope of protection of personal information and the duty of delivery service company during treating of personal information of buyer. Also, it is tried to make an improvements for protecting of personal information. Actually, in the article 25 of ｢Act on Promotion of Information and Communications Network Utilization and Information Protection, Etc.｣, the delivery service that was requested from online company was defined as an Entrusted Handling of Personal Information. So online company has some duties such as management and supervision of an entrusted handling of personal information. But because this article was intented every third party of an entrusted handling of personal information, it is not proper to apply to delivery service that has special area. That is, when delivery service is processed, the personal information is revealed in whole process. Therefore, personal information should be kept more carefully and especially encoded. In the same way, for protection of personal information of the delivery service in an entrusted handling, the access authority should be departmentalized depending on authority, and prohibit to the use of station for other purpose. Lastly, the provisions applicable mutatis mutandis should be modified by fitting a delivery service.