Computer-aided vorticity measuring system based on hotwire anemometry has been developed and used for investigation of time-dependent vortical flow field of a traveling vortex ring. The vorticity distributions obtained are visualized on computer graphics and are recorded as animation film. Instantaneous vorticity contours measured are compared with Schlieren photographs taken at the correspponding time instant. This system is applicable for research of various vortical flow field.