To solve poor usability in information selection with a conventional small PDA, in which many gadgets of this kind suppose that the small PDA is placed on a desk to be used or being with one hand and operated by the other hand, for example, when desired of browsing own schedule or inform the opposite party telephone number of a third party and the like during a call.

An item displayed on a liquid crystal display screen or a function selection button, a return button to let a resultant display selected by the selection button go back to the previous status and a power supply button are arranged on the side of the small PDA, specifically at the position where its operation with a thumb is possible, when the small PDA is held with one hand. This enables intended operation to be performed, by changing the direction of pressure applied to each button.