A knee joint supporter includes a first anchor having a loop face, a main body including second anchor, first supporting and second supporting, connections joining the anchors and connecting the first anchor and main body, a first engaging joined to the second supporting and having a hook face to stick to the loop face, a second engaging joined to the first anchor and having a hook face to stick to the loop face, and a third engaging joined to the first supporting and having a hook face to the loop face. The first anchor fastens around a thigh of a wear. The second anchor extends below popliteal region. The first supporting extends on one side from below part corresponding to a patella, and the second supporting extends on the other side of the part corresponding to the patella and crosses the first supporting below the part corresponding to the patella.