A mobile radio communication apparatus includes a first housing, a second housing foldable over the first housing, and a hinge part that foldably connects the second housing to the first housing around a rotational center axis, wherein the hinge part includes a one touch opening part that automatically opens the second housing from a folded state by a first angle relative to the first housing around the rotational center axis in a non-stop motion, and an auxiliary rotational part that rotates the second housing around an orthogonal shaft orthogonal to the rotational center axis of the hinge part.