To provide a damper mechanism capable of obtaining a predetermined damping force by suppressing a change of the damping force which damps the rotation force of a main unit even if an elastic force of a braking means is changed, and to provide an image processing apparatus equipped with this mechanism.

The damper mechanism 80, which is provided between an upper unit 40 and a main unit part 50 supported pivotally on each other at each back surface side, comprises an arm 81, a friction member 86, a curved guide surface 82C, and a spring 83. The arm 81 rotates in the prescribed direction inside L1-L3 surface with the rotation of the upper unit 40 and the main unit part 50. The friction member 86 and the curved guide surface 82C holds the arm 81 in the holding direction different from the prescribed direction. The spring 83 generates a holding force which makes the friction member 86 and the curved guide surface 82C hold the arm 81.