Provided is a control over access to a Device Management (DM) tree of a client. The client receives a secure area creation password from a server, creates a secure area by using the received creation password, and moves the DM tree to the secure area. In addition, the client receives a secure area access password from the server, accesses the secure area by using the received access password, and performs a remote management through a DM command received from the server. The authority to access the DM tree is given to only the client acquiring a password from the server, which effectively prevents an unauthorized change of a DM tree.