An automatic analyzer comprising: a reagent dispensing unit configured to aspirate a reagent from a reagent vessel that contains the reagent, and discharge the reagent into a reaction vessel that contains a reaction liquid containing a sample, the sample being one of various types of control samples; a storage unit configured to store, for each one of the various types of the control samples, concentration-related information (500, 1100) indicating a tolerance range (504, 505), a reagent degradation threshold and a bubble generation threshold for a concentration of a component to be measured contained in the sample; a detection unit configured to detect a measurement concentration that is a concentration of the component to be measured contained in the reaction liquid; and a determination unit configured to determine whether an abnormality occurs in the reagent vessel based on a result of whether the measurement concentration in a current measurement is within the tolerance range; characterized in that the abnormality is the generation of a bubble in the reagent vessel or the possibility of deterioration of the reagent contained in the reagent vessel; wherein the determination unit is configured to determine that a bubble has been generated in the reagent vessel, when the absolute value of the difference between the measurement concentration in a previous measurement and the measurement concentration in the current measurement is above the bubble generation threshold; wherein the determination unit is configured to determine that there is the possibility of deterioration in the reagent vessel, when the absolute value of the difference between the measurement concentration in the previous measurement and the measurement concentration in the current measurement is above the reagent degradation threshold and equal to or below the bubble generation threshold; and wherein the determination unit is configured to determine that the abnormality may both be the generation of a bubble in the reagent vessel or the possibility of deterioration in the reagent vessel, when the absolute value of the difference between the measurement concentration in the previous measurement and the measurement concentration in the current measurement is equal to or below the reagent degradation threshold. a reagent dispensing unit configured to aspirate a reagent from a reagent vessel that contains the reagent, and discharge the reagent into a reaction vessel that contains a reaction liquid containing a sample, the sample being one of various types of control samples; a storage unit configured to store, for each one of the various types of the control samples, concentration-related information (500, 1100) indicating a tolerance range (504, 505), a reagent degradation threshold and a bubble generation threshold for a concentration of a component to be measured contained in the sample; a detection unit configured to detect a measurement concentration that is a concentration of the component to be measured contained in the reaction liquid; and a determination unit configured to determine whether an abnormality occurs in the reagent vessel based on a result of whether the measurement concentration in a current measurement is within the tolerance range; characterized in that the abnormality is the generation of a bubble in the reagent vessel or the possibility of deterioration of the reagent contained in the reagent vessel; wherein the determination unit is configured to determine that a bubble has been generated in the reagent vessel, when the absolute value of the difference between the measurement concentration in a previous measurement and the measurement concentration in the current measurement is above the bubble generation threshold; wherein the determination unit is configured to determine that there is the possibility of deterioration in the reagent vessel, when the absolute value of the difference between the measurement concentration in the previous measurement and the measurement concentration in the current measurement is above the reagent degradation threshold and equal to or below the bubble generation threshold; and wherein the determination unit is configured to determine that the abnormality may both be the generation of a bubble in the reagent vessel or the possibility of deterioration in the reagent vessel, when the absolute value of the difference between the measurement concentration in the previous measurement and the measurement concentration in the current measurement is equal to or below the reagent degradation threshold.