<p>An object of the present invention is to provide an automatic analyzer which measures blank values for each vessel to reduce analysis time. The automatic analyzer comprises: a vessel for storing a sample and a reagent; a cleaning mechanism for cleaning the vessel and; an analysis mechanism for performing photometric inspection of reaction of the reagent and the sample; wherein the automatic analyzer includes a blank value comparison function for comparing a preceding blank value with a succeeding blank value. The preceding blank value is measured before photometric inspection of the reaction in the initial starting operation initially performed. The succeeding blank value is measured after photometric inspection of the reaction in the running operation subsequently performed after the initial starting operation.</p>
