A data collation apparatus has: a collation unit which calculates a similarity between input data measured by a measurement apparatus and each of registered data; and a calculation unit which adjusts, if a similarity of first registered data of which similarity with the input data is highest is lower than a first threshold, and a difference between the similarities of the first registered data and second registered data of which similarity with the input data is second highest is smaller than a predetermined value, or if a degree of separation to indicate a distance between the similarity of the first registered data and a similarity distribution of a group of registered data items of which similarities with the input data are second highest or lower is smaller than a predetermined value, the parameters of the measurement apparatus, and instructs the measurement apparatus to remeasure the measurement subject.