A knee joint supporter which is made of a tubular knitted fabric that is knitted in circular knitting, and adapted to come into close contact with the body surface of a wearer, thereby assisting a knee joint, the knee joint supporter comprising: a first anchor section which is knitted to go around one end of the tubular knitted fabric and adapted to make the tubular knitted fabric be tightened on the thigh of the wearer; a second anchor section which is knitted to go around the other end of the tubular knitted fabric and adapted to make the tubular knitted fabric be tightened on the lower thigh of the wearer; a base fabric section which is knitted between the first anchor section and the second anchor section; and in relation to the first anchor section, the second anchor section and the base fabric section, the stretch resistances of the first anchor section and the second anchor section in a circumferential direction of the tubular knitted fabric are larger than the stretch resistance of the base fabric section in the circumferential direction of the tubular knitted fabric; a supporting section which is knitted between the first anchor section and the second anchor section; in relation to the supporting section and the base fabric section, the stretch resistance of the supporting section in a length direction of the tubular knitted fabric is larger than the stretch resistance of the base fabric section in the length direction of the tubular knitted fabric, characterized in that the supporting section is knitted together with the base fabric section between the first anchor section and the second anchor section and in an approximate U-shape or V-shape such that a first end of the supporting section is connected to the first anchor section and a second end of the supporting section is connected to the first anchor section at a different location so that the supporting section is adapted to surround the patella of the wearer such that a lower portion of the supporting section is adapted to be disposed below a bottom section of the patella, a first side of the supporting section is adapted to be disposed on a first side of the patella, and a second side of the supporting section is adapted to be disposed on a second side of the patella. a first anchor section which is knitted to go around one end of the tubular knitted fabric and adapted to make the tubular knitted fabric be tightened on the thigh of the wearer; a second anchor section which is knitted to go around the other end of the tubular knitted fabric and adapted to make the tubular knitted fabric be tightened on the lower thigh of the wearer; a base fabric section which is knitted between the first anchor section and the second anchor section; and in relation to the first anchor section, the second anchor section and the base fabric section, the stretch resistances of the first anchor section and the second anchor section in a circumferential direction of the tubular knitted fabric are larger than the stretch resistance of the base fabric section in the circumferential direction of the tubular knitted fabric; a supporting section which is knitted between the first anchor section and the second anchor section; in relation to the supporting section and the base fabric section, the stretch resistance of the supporting section in a length direction of the tubular knitted fabric is larger than the stretch resistance of the base fabric section in the length direction of the tubular knitted fabric, characterized in that the supporting section is knitted together with the base fabric section between the first anchor section and the second anchor section and in an approximate U-shape or V-shape such that a first end of the supporting section is connected to the first anchor section and a second end of the supporting section is connected to the first anchor section at a different location so that the supporting section is adapted to surround the patella of the wearer such that a lower portion of the supporting section is adapted to be disposed below a bottom section of the patella, a first side of the supporting section is adapted to be disposed on a first side of the patella, and a second side of the supporting section is adapted to be disposed on a second side of the patella.