With this biological sample measuring device, the determination section performs measurement at specific intervals in a first measurement period from the start of measurement until a first time, and performs measurement at specific intervals in a second measurement period that comes after the first measurement period, calculates the difference between the measurement values in corresponding specific periods, and finds a plurality of first difference determination values, on the basis of a plurality of current values measured in the first measurement period and a plurality of current values measured in the second measurement period, finds a second difference determination value by finding the difference at specific intervals in the plurality of first difference determination values, and determines whether or not a reagent movement error and/or exposure error of the biological sample measurement sensor has occurred, on the basis of the first and second difference determination values.