A mobile terminal includes a controller for switching a current screen theme of a GUI screen of an application program to a prospective screen theme, the GUI screen including two or more GUI tools of a same type, and a storage for storing a plurality of screen theme definition data sets, wherein the controller loads one of the plural screen theme definition data sets stored in the storage, which screen theme defines the prospective screen theme, into a memory region reserved for the application program, and draws the two or more GUI tools of a same type included in the GUI screen using the loaded screen theme definition data set, which is stored in the memory region for the application program. As a result, the entire GUI screen of an application is displayed on a common screen theme and a screen theme can be switched rapidly, using a reduced memory capacity.