A device management (DM) system using a log management object and a method for effectively generating and controlling logging data in the system are disclosed. A DM server includes only information that a client can transfer processing of a corresponding command to a logging sub-tree manager in the logging data storage command and transmits it, and an accurate location at which the logging data is to be stored is determined by the logging sub-tree manager by itself by using control information of the logging sub-tree upon receiving the logging data storage command. Each node storing the logging data has a source attribute value and a reason attribute value. Accordingly, the DM server or a scheduling context does not involve in a complicate logging data storage procedure, and when logged node is checked, the particulars of the logged data can be easily recognized.