An automated analysis device configured to measure a liquid sample containing magnetic particles and a substance to be measured, the automated analysis device comprising: a magnetic separation device configured to separate the magnetic particles from the liquid sample; an aspiration nozzle configured to aspirate the liquid sample from a vessel containing the liquid sample after the magnetic particles are separated; a dispensing nozzle configured to dispense a cleaning solution to the vessel after the aspiration nozzle aspirates the liquid sample; and an agitating mechanism configured to perform agitating by rotating the vessel in which the cleaning solution is dispensed; the automated analysis device further comprising a control unit configured to control the aspiration nozzle, the dispensing nozzle, and the agitating mechanism, wherein, the control unit is configured to: after the magnetic separation device has separated the magnetic particles from the liquid sample, control the dispensing nozzle to dispense the cleaning solution and control the agitating mechanism to rotate the vessel, so as to perform a cleaning step for removing a substance other than the magnetic particles from the liquid sample, and the cleaning step is performed a plurality of times on the same liquid sample, reduce an amount of the cleaning solution each time the cleaning step is performed, and cause the agitating mechanism to operate in such a way that the magnetic particles remaining on a wall surface of the vessel in the cleaning step are captured by the cleaning solution in the next cleaning step, wherein either the control unit is further configured to cause the agitating mechanism to operate in such a way that a rotation speed of the vessel is increased each time the cleaning step is performed on the same liquid sample, or the control unit is further configured to reduce a rotation speed of the vessel more rapidly when the last cleaning step performed on the same liquid sample is completed than when the cleaning step performed before the last cleaning step is completed. a magnetic separation device configured to separate the magnetic particles from the liquid sample; an aspiration nozzle configured to aspirate the liquid sample from a vessel containing the liquid sample after the magnetic particles are separated; a dispensing nozzle configured to dispense a cleaning solution to the vessel after the aspiration nozzle aspirates the liquid sample; and an agitating mechanism configured to perform agitating by rotating the vessel in which the cleaning solution is dispensed; the automated analysis device further comprising a control unit configured to control the aspiration nozzle, the dispensing nozzle, and the agitating mechanism, wherein, the control unit is configured to: after the magnetic separation device has separated the magnetic particles from the liquid sample, control the dispensing nozzle to dispense the cleaning solution and control the agitating mechanism to rotate the vessel, so as to perform a cleaning step for removing a substance other than the magnetic particles from the liquid sample, and the cleaning step is performed a plurality of times on the same liquid sample, reduce an amount of the cleaning solution each time the cleaning step is performed, and cause the agitating mechanism to operate in such a way that the magnetic particles remaining on a wall surface of the vessel in the cleaning step are captured by the cleaning solution in the next cleaning step, wherein either the control unit is further configured to cause the agitating mechanism to operate in such a way that a rotation speed of the vessel is increased each time the cleaning step is performed on the same liquid sample, or the control unit is further configured to reduce a rotation speed of the vessel more rapidly when the last cleaning step performed on the same liquid sample is completed than when the cleaning step performed before the last cleaning step is completed. after the magnetic separation device has separated the magnetic particles from the liquid sample, control the dispensing nozzle to dispense the cleaning solution and control the agitating mechanism to rotate the vessel, so as to perform a cleaning step for removing a substance other than the magnetic particles from the liquid sample, and the cleaning step is performed a plurality of times on the same liquid sample, reduce an amount of the cleaning solution each time the cleaning step is performed, and cause the agitating mechanism to operate in such a way that the magnetic particles remaining on a wall surface of the vessel in the cleaning step are captured by the cleaning solution in the next cleaning step, wherein either the control unit is further configured to cause the agitating mechanism to operate in such a way that a rotation speed of the vessel is increased each time the cleaning step is performed on the same liquid sample, or the control unit is further configured to reduce a rotation speed of the vessel more rapidly when the last cleaning step performed on the same liquid sample is completed than when the cleaning step performed before the last cleaning step is completed.