Provided is a marker generation device which has a feature comparison means and a marker pattern generation means. The feature comparison means disposes feature points extracted from an image in a predetermined space, sets parts in which the number of feature points in the predetermined space is equal to or less than a predetermined number as singular features, disposes feature points extracted from an identifier in the predetermined space, and counts the number of feature points that coincide with the singular features. The marker pattern generation means converts the structure of the identifier and extracts the feature points from the converted identifier. The feature comparison means disposes the feature points extracted from the converted identifier in the predetermined space, counts the number of feature points that coincide with the singular features, and selects, as a marker for detection, an identifier having the most counts from among identifiers before conversion and one or two or more identifiers that have been converted.