A portable information device includes: a first chassis; a second chassis adjacent to the first chassis, the second chassis coupled to the first chassis so as to be relatively rotatable between a flat form in which the first and second chassis are arranged side by side in a direction perpendicular to a surface direction thereof and a stacked form in which the first and the second chassis are stacked to overlap each other in the surface direction thereof; a spine member provided across adjacent end portions of the first and second chassis, the spine member covering a gap generated between the adjacent end portions of the first and second chassis in the stacked form; and a cushion portion provided in at least a part of a front side of the spine member, the cushion portion facing an internal space generated between the first and second chassis in the stacked form.