1. An apparatus for performing multi-tasking, comprising: a display unit including a first region in which an initial application is executed during a multi-tasking's initial mode, and a second region displaying the plurality of applications, wherein at least one of the plurality of applications displayed in the second region is executed in the first region during a multi-tasking's execution mode; a task manager for executing a transfer of the at least one of the plurality of applications displayed in the second region into the first region during the multi-tasking's execution mode and for performing a transition to the multi-tasking's initial mode when the background is selected via one touch operation; and a controller for controlling multi-tasking to be performed through the task manager in the multi-tasking's initial/execution mode.