An automatic analyzer comprising: a dispensing mechanism (50, 60, 70) having a dispensing nozzle and adapted to dip the dispensing nozzle in a dispensing target contained in a container, aspirate the dispensing target, and discharge the dispensing target to a reaction container; a pressure sensor for detecting pressure inside the dispensing nozzle of the dispensing mechanism; a storage unit for storing multiple items of determination-purpose reference data used in determining whether or not the dispensing mechanism is abnormal; a determination-purpose reference data selection unit adapted to select one item of the determination-purpose reference data from the multiple items of the determination-purpose reference data stored in the storage unit; and an abnormality determination unit adapted to determine whether or not the dispensing mechanism is abnormal, based on the selected determination-purpose reference data and a detection result from the pressure sensor when the dispensing mechanism dispenses a dispensing target used in analysis, wherein the abnormality determination unit is adapted to determine whether or not the dispensing mechanism is abnormal, based on the comparison result of the statistical distance between the detection result from the pressure sensor when the dispensing mechanism dispenses the dispensing target used in analysis and the selected determination-purpose reference data, with a predetermined threshold value; characterized in that the determination-purpose reference data selection unit is adapted to select one item of the determination-purpose reference data from the multiple items of the determination-purpose reference data stored in the storage unit based on a detection result from the pressure sensor when the dispensing mechanism dispenses a reference dispensing target configured to contain a known ingredient. a dispensing mechanism (50, 60, 70) having a dispensing nozzle and adapted to dip the dispensing nozzle in a dispensing target contained in a container, aspirate the dispensing target, and discharge the dispensing target to a reaction container; a pressure sensor for detecting pressure inside the dispensing nozzle of the dispensing mechanism; a storage unit for storing multiple items of determination-purpose reference data used in determining whether or not the dispensing mechanism is abnormal; a determination-purpose reference data selection unit adapted to select one item of the determination-purpose reference data from the multiple items of the determination-purpose reference data stored in the storage unit; and an abnormality determination unit adapted to determine whether or not the dispensing mechanism is abnormal, based on the selected determination-purpose reference data and a detection result from the pressure sensor when the dispensing mechanism dispenses a dispensing target used in analysis, wherein the abnormality determination unit is adapted to determine whether or not the dispensing mechanism is abnormal, based on the comparison result of the statistical distance between the detection result from the pressure sensor when the dispensing mechanism dispenses the dispensing target used in analysis and the selected determination-purpose reference data, with a predetermined threshold value; characterized in that the determination-purpose reference data selection unit is adapted to select one item of the determination-purpose reference data from the multiple items of the determination-purpose reference data stored in the storage unit based on a detection result from the pressure sensor when the dispensing mechanism dispenses a reference dispensing target configured to contain a known ingredient.