Damage to a bearing section and cases is able to be prevented in a portable terminal device in which two cases are mutually and rotatably coupled about an axis that extends in the direction in which they overlap, and the range of the relative movement of the two cases is restricted. This portable terminal device is provided with two cases arranged so as to be able to be mutually overlapped, a coupling unit that mutually and rotatably couples the two cases about an axis extending in the direction of overlapping, and a reinforcing member that is fixed within one case of the two cases. The coupling unit is provided on the other case of the two cases, has a hollow rotation shaft having the axis for its center line and a bearing section that rotatably axially supports the rotation shaft, and the bearing section is attached to the reinforcing member.