1. A mobile communications terminal, comprising: a controller configured to control switching between an active state of an application program, a non-active state of the application program, and a rest state of the application program; and an input unit configured to instruct a state transition between said active state, said non-active state and said rest state, wherein said controller executes control for switching the execution state of said application program between the active state, non-active state and the rest state, in accordance with instructions from said input unit, wherein, in the active state of the application program, the application program is executed and permitted to process data inputted by a key and a native application program that controls a communication function of the mobile communication terminal is not permitted to process the data inputted by the key, in the non-active state of the application program, the application program is executed and not permitted to process data inputted by the key and the native application program that controls the communication function of the mobile communication terminal is permitted to process the data inputted by the key, and in the rest state of the application program, the application program is halted and not permitted to process data inputted by the key and the native application program that controls the communication function of the mobile communication terminal is permitted to process the data inputted by the key.