The three-dimensional structure of the heliospheric current sheet is constructed for Carrington rotations 1647, 1654, 1661,1667, 1693, 1699, and 1719. These rotations are chosen from different epochs during the sunspot cycle 21, so that one can infer geometrical changes of the current sheet during a sunspot cycle. Only for relatively simple neutral lines on the source surface, do the structures of the current sheet approximate to those envisaged by Svalgaard and Wilcox [1976> and Thomas and Smith [1981>.