In an information terminal device, tap information in accordance with a pattern of a tapping operation of a user is acquired, and unlocking information is acquired in which unlocking tap information items, each of which functions as an unlocking key for each of applications, are associated with the corresponding applications. If a predetermined condition is satisfied, the present device is changed from a normal state to a locked state. If the present device is in the normal state and the acquired tap information coincides with any one of the unlocking tap information items, the present device is changed from the locked state to a limited unlocked state in which at least the application associated with the relevant unlocking tap information item is operable.