An apparatus of setting multi-channels in a network system includes a mobile station transmitting at least one piece of channel information on a request message, wherein the request message requests to set a connection identifier for a communication service; and a control station calculating a bandwidth according to number of channels using the request message received from the mobile station and setting the calculated bandwidth as a service bandwidth of the connection identifier. The control station such as an ACR supports multi-channels through one frame structure (i.e., a communication structure of a connection identifier) and thus radio resources (e.g., bandwidth) to be provided to the mobile station are reduced.