A substrate is cleaned by supplying an ultrasonically-agitated cleaning liquid onto the substrate from a nozzle provided above the substrate while spinning the substrate. By shortening the blanking period, the amount of time available for sending data in each scan line is increased, enabling the system to send more data over each channel. A joint between the big end and the rod main body is located closer to the small end than is an end of the curved section facing the rod main body.