Simple, high-precision cell tracking is realized. Provided is a method for tracking cells, comprising an image acquisition step (S1) of acquiring a plurality of observation images including a plurality of cells in the field of view at certain time intervals; a feature analysis step (S2) of analyzing predetermined brightnesses of the individual cells in the observation images acquired in the image acquisition step (S1); a grouping step (S3) of grouping the cells for each of the observation images on the basis of the brightnesses analyzed in the feature analysis step (S2) and a predetermined threshold value for classifying the brightnesses; and an associating step (S4) of associating, for each of the groups divided in the grouping step (S3), the cells whose morphological features are substantially the same between the observation images acquired at different times.