To provide an information processor that smoothly inverts a display part.

In the information processor, one edge of a 1st arm 13 is supported to a device body by a 1st shaft in a freely rotatable way, one edge of 2nd arm 14 is supported to the other edge of the arm 13 by a 2nd shaft b in a freely rotatable way and a display part 12 is supported to the other edge of the arm 14 by a 3rd shaft c in a freely rotatable way. In such cases, a lock bar 16 is provided inside the arm 13 in a slidable way, and a lock hole 23 which interfits with the tip of the lock bar 16 is provided on the arm 14. The locking or unlocking of the arm 14 to the arm 13 is selectively performed by sliding a knob part 19 that is integrated with the bar 16 manually.