A portable information terminal for inputting complicated data is disclosed. The portable terminal comprises a main housing having first and second top surfaces formed in a step form; a data input housing disposed on the main housing in a foldable manner and having top and bottom surfaces; and a hinge for joining the data input housing to the main housing in a rotatable manner. The second top surface of the main housing has a first plurality of keys, the top surface of the data input housing has a second plurality of keys, and the bottom surface of the data input housing has a third plurality of keys.