To clean a nozzle that is part of an automated analyzer and is provided with both a tubular discharge unit that discharges a cleaning liquid and a tubular suction unit that suctions in cleaning liquid that was discharged from the discharge unit and is running down an outer surface, first the discharge unit is made to start discharging, and then in parallel with said discharging, the suction unit is made to start suctioning. After the suction unit has suctioned in the cleaning liquid running down the aforementioned outer surface for a prescribed length of time, the suctioning is temporarily stopped. Next, after a prescribed amount of the cleaning liquid has accumulated in a cleaning tank, the discharging is stopped, and with the suction unit immersed in the cleaning liquid accumulated in the cleaning tank, the suctioning is restarted.