Convalescence of distal radius bone fracture, which is major disease for elderly people, requires speedy improvement of the contracture for wrist joint angles. The contracture is the case that wrists stiffen up and the range of their motion tends to be restricted by fixing them for long time after bone fracture. Recently, traction of the wrist during flexing and extending the wrist joint is considered to be efficient as the rehabilitation procedure. Previously, we developed an equipment that can apply the constant traction force to the wrist during flexing and extending the wrist joint. By using the equipment, we observed the dynamic motion of carpals in the wrist by radiography and found that the ratio of displacement of radius - lunate joint (R-L joint) to that of wrist angle increases by the traction. However, as the obtained images by radiography were not so clear and 2 dimensional data by projecting the texture of carpal, the displacement and rotation of carpal couldn't be measured precisely. We have developed a new equipment that can hold a wrist joint being pulled at flexion or extension posture for MRI photography. MRI can take detail 3 dimensional images. By using the equipment, the study reveals that lunar, which constitutes R-L joint as a major carpel, rotates by traction of the wrist and its rotation extends the motion range of R-L joint to dorsiflexion side. Furthermore, the interosseous distance of capitate - lunate joint (C-L joint) tends to extent by the traction at neutral and dorsiflexion positions, and it may have influence on the extension of the motion range of R-L joint.