A portable information device that can stably support a display is disclosed. The portable information device includes a first chassis member; a second chassis member; a hinge mechanism; a display whose back surface is supported by front surfaces of a first support plate and a second support plate; an alignment part that aligns the front surfaces between one edge of the first support plate and one edge of the second support plate adjacent to each other, in a flat form; a first support part that supports the first support plate relative to the first chassis member; and a second support part that supports the second support plate relative to the second chassis member. At least one of the first support part and the second support part includes a floating part that supports a corresponding support plate relative to a corresponding chassis member in a floating state.