To provide a support for a joint orthosis with a new function capable of being rotated in the same direction in bending or stretching the joint of an elbow or knee wearing a joint orthosis without hindrance and without being rotated in the direction of returning even if the force is applied in the reverse direction, and capable of fixing and releasing the fixing of the joint at an arbitrary rotation position.

In the support for the joint orthosis, the lower end part of an upper support and the upper end part of a lower support are connected to each other rotatably with a joint having the rotation shaft perpendicular to the longitudinal direction of the supports. The joint has a non-return mechanism to be rotated in one direction but not to be rotated in the reverse direction and a clutch mechanism for releasing the function of the non-return mechanism. Specifically, it is preferable that the joint has a reversible direction setting mechanism capable of setting the operation direction either in the forward direction or in the backward direction and converting the setting.