The present invention makes it possible for a degree of difficulty or a target period of a text to be estimated accurately with a desired granularity. A feature quantity extracting unit 230 extracts a feature quantity including a word acquisition period from text in a picture book, and a degree of difficulty estimating unit 232 estimates a degree of difficulty of the text in the picture book on the basis of the extracted feature quantity, and a degree of difficulty estimating model learned in advance.
DEGREE OF DIFFICULTY ESTIMATING DEVICE, AND DEGREE OF DIFFICULTY ESTIMATING MODEL LEARNING DEVICE, METHOD, AND PROGRAM