Provided is an automatic analyzer that has a plurality of mechanisms including a mechanism that suctions reaction waste liquid and a mechanism that suctions cleaning liquid, etc. on a sample and a probe surface, the automatic analyzer reducing pressure in a vacuum tank using a pressure-reducing pump, etc., and suctioning waste liquid by negative pressure in the vacuum tank. A contact point of a vacuum switch that is provided in the vacuum tank is closed when the pressure in the vacuum tank reaches a specified negative pressure, and then the analyzer becomes ready for analysis. If any flow path portion of any mechanism that connects with the vacuum tank becomes clogged, suctioning operation cannot be performed properly and analysis performance is affected. The vacuum pump is switched off at a timing at which each solenoid valve connecting to the vacuum pump is individually opened, and the time that elapses before the pressure in the vacuum tank reaches the specified negative pressure is measured. The measured time is compared with parameters in a normal case, and the presence or absence of an anomaly is determined.