The present invention relates to a knee joint assistance device which comprises: two rotation regulation plates provided on both sides of an upper support; a first link of which both ends thereof are rotatably linked by a hinge pin; a second link of which both ends thereof are rotatably linked by the hinge pin; two angle adjustment parts rotatably coupled to a central shaft coupled to the rotation regulation plates; and a regulation cap covering so that the angle adjustment part is not deviated from the rotation regulation plates, thereby allowing a user to safely walk without inconvenience.
