1. A dictionary learning device comprising: a score calculation unit that calculates a matching score representing a similarity-degree between a sample pattern which is a sample of a pattern which is likely to be subjected to a pattern matching processing and a degradation pattern resulting from a degrading processing on the sample pattern; and learning unit that, based on the calculated matching score and the degradation pattern, learns a quality dictionary which is used in a processing to evaluate a degradation degree of a matching target pattern of being target to be subjected to the pattern matching processing.