Disclosed are an apparatus for measuring biodata and a method for measuring biodata using an algorithm for improving reproducibility. The method for measuring biodata, according to one embodiment of the present invention, involves: determining whether or not a reaction is stabilized on the basis of the mean ratio of the change in a predetermined section of the early stage of measurement to determine a reaction ending time; and adding a correction value to the value measured at the determined reaction ending time to obtain a final measurement value, thereby reducing measurement errors and improving reproducibility and data reliability.