PURPOSE: A piston type knee brace is provided, which can protect patient's knee from the external impact and help stretching and bending movement of the knee. CONSTITUTION: A piston type knee brace comprises: a connection plate locating in wearer's knee articulation in wearing; a support bar which is connected to one side of the connection plate in order to be rotated; a rotation bar locating in one side of the femoral region and shinbone part; a housing(310) fixed in the support bar; a connection rod(340) in which one end rotates and the other end ascends and descend as the rotation bar revolves; a piston(330) inserted and installed in an elevating space; and an elastic body inserted and installed in the elevating space.
