A portable terminal device of the invention has a first casing that has a first
display part and a second casing that has a key operation part. The first casing
and the second casing are constructed in such a form as to be rotatable around
a hinge portion, which has a second display part. In a state where the terminal
device is open, the first display part is visually recognizable by the user, and
in a state where the terminal device is closed, the second display part is visually
recognizable by the user.