In the event of a suspected abnormality in the device, sample or reagent, a laboratory technician had to examine the abnormal reaction process data item by item, and infer the cause of the abnormality, which took effort and time in some cases. Abnormality judgment is assisted using: indicator computation means that computes an indicator indicating a feature parameter of a given waveform by applying a pre-defined evaluation formula to time series data of photometric values; relative indicator computation means that computes a value indicating a relationship of the indicator of target data to the indicator computed in the past; and indicator display means that simultaneously displays a value computed by the indicator computation means and the value computed by the relative indicator computation means. According to the present method, which is a method for assisting judgment of abnormality wherein a feature parameter of a given absorbance change is computed, it can be made easier to find certain abnormalities, and it becomes possible to attain more efficient device maintenance and improved device reliability without the addition of any new parts.