In a portable communication terminal capable of assuming a state where a first casing 1 and a second casing 2 connected rotatably overlap substantially and a state where they are rotated relative to each other by 90° from the former state, the second casing 2 including a display unit 3 is rotated by about 90°, so that the display unit 3 is made horizontally long, thus enabling the displaying with good visibility. At the same time, the rotation causes the first casing 1 at an upper edge thereof not to overlap with the second casing 2, and an antenna 5 is disposed at the not-overlapping portion, thus increasing an electrical volume of the antenna to provide broad-band and good antenna characteristics. Since the antenna 5 overlaps with the second casing 2 when in normal use, the antenna does not protrude, thus keeping the terminal compact and slim to provide excellent portability. In the portable communication unit provided with a rotatable casing including a display unit, the terminal as a whole can be kept compact so as not to let an antenna protrude therefrom both when in normal use and during standby, the display with a high level of visibility is enabled depending on the contents, and good antenna characteristics can be achieved.