Robot fingers with many joints driven by a small number of motors are useful for low-cost, light and high-performance robot hands. We propose a robot finger with many joints driven by one motor. Many kinds of motion of the finger can be selected using shape memory gel and tendon-driven mechanism. The rotation of one joint, two joints and many joints of the finger are shown in this paper. Rotatable joint can be selected from many joints. The rolling motion of the finger can be done when many joints rotate in the same direction. The routes of the tendon strings are designed so that the number of required motors can be reduced. The new robot finger has a skeleton while our previous finger does not have a skeleton. The advantages and disadvantage of the skeleton are also discussed in this paper. Experiments of one finger shows its ability of various motion. We also design a prototype robot hand using three fingers and show the motion for some kinds of objects.