A sustaining manipulator arm capable of being set on a ground includes a first linkage set. The first linkage set includes a first link, a second link, a first ball joint, a second ball joint, a third link, and a first elastic element. A first end of the first link is connected to a first revolution element, and the first revolution element has a first revolution direction. A first end of the second link is connected to a second revolution element. The second revolution element has a second revolution direction. The first revolution direction and the second revolution direction are the same direction, and the first revolution element and the second revolution element are on a first plane. The first ball joint is set in the first link. The second ball joint is set in the second link. A first end of the third link is connected to the first ball joint. A second end of the third link is connected to the second ball joint, and the third link is parallel to the first plane. The two ends of the first elastic element are respectively attached to the first link and the third link, and the first elastic clement makes the first linkage set reach static equilibrium.