A folder type mobile telephone and control method therefor are provided which utilize an auxiliary display unit viewable whether the folder is opened or closed. The folder type mobile telephone includes an auxiliary display unit and a main body having a main display unit. The folder type mobile telephone includes an opening at a position corresponding to the auxiliary display unit. The folder type mobile telephone may include a wheel button formed at one side of the main body to input user commands to the auxiliary display unit. A transparent window may be formed at the opening to protect the auxiliary display unit. Regardless of whether the folder is opened or closed, a user can view, and control the auxiliary display unit via wheel button inputs. Since the auxiliary display unit is formed on the main body, the relative thickness of the folder can be reduced to make the folder type mobile telephone compact.