We have been developing a casting manipulator which includes a flexible string in the link mechanism in order to enlarge the work space of the manipulator. Like the casting motion of fly fishing, the necessary motion of the gripper, which is attached at the end of the string, is generated by swinging a rigid link The gripper is thrown to the target by releasing the string at the suitable time. In this paper we deal with the basic swing motion control of the casting manipulator. We describe a method of oscillating the casting manipulator by considering it as a two-degrees-of-freedom nonholonomic system By planning a time-periodic reference for the second joint while controlling the first joint, the desired swing motion of the system can be generated. The method was evaluated by comparing the results of numerical simulation and those of experiments using the casting manipulator hardware.