Disclosed is a handwritten contents aggregation device including: an obtaining unit configured to obtain a first file and a second file in each of which written information indicating handwritten contents is added to a same original file; and a processor configured to: analyze the first file and the second file and extract the written information from the first file and the second file, prepare a third file by aggregating the written information extracted from the first file and the written information extracted from the second file in the original file, and output the third file.