A tooth soundness determination assistance device (20) includes: a gray scale conversion unit (21) for converting a fluorescent image obtained by imaging the fluorescence of a tooth irradiated with excitation light into a gray scale image； a gray scale value acquisition unit (22) for acquiring gray scale values at a reference point and a plurality of evaluation points in an image of the tooth in the gray scale image； a normalization unit (23) for normalizing the gray scale values at the plurality of evaluation points by the gray scale value at the reference point； and a tooth soundness determination data generation unit (24) for generating tooth soundness determination data visually indicating the gray scale value at the reference point and the normalized gray scale values at the plurality of evaluation points.
