A problem to be solved is to assist input of information by a user. An information processing device of one embodiment includes a keyword sequence generator generating a keyword sequence by performing morphological analysis on text data in natural language; a category information sequence generator acquiring category information corresponding to each keyword of the keyword sequence based on a database in which keywords are associated with category information and generating a category information sequence; the pattern extractor selecting a category information sequence pattern from category information sequence patterns according to correlation between the category information sequence and each category information sequence pattern; and a determiner comparing the selected category information sequence pattern with the category information sequence and generating presentation information according to a difference between the selected category information sequence pattern and the category information sequence.