Mobile communication device and control method thereof

A mobile communication terminal and a controlling method thereof are provided to convert a command mapped with a key used for inputting adaptively, according to an operation mode, thereby efficiently controlling operation of the mobile communication terminal. Plural keys(140) are configured for a user to input different commands in the first operation mode which is an idle mode and in the second operation mode which is a multi-tasking mode. A memory(170) stores key mapping information where commands corresponding to each input of the plural keys are mapped according to each operation mode. A mode conversion detector(160) determines whether to convert an operation mode to the second operation mode from the first operation mode. A controller(180) controls the mobile terminal, so that a particular key is converted into key mapping information used in the second operation mode, when the operation mode is converted, and key mapping information used in the first operation mode is maintained for the rest of the keys.