1. An information processing device comprising: a communication unit which transmits textual information; a schedule storage unit which stores schedule information; a keyword storage unit which stores multiple keywords that are classified into multiple categories; a keyword extraction unit which extracts keywords from the textual information transmitted by the communication unit on the basis of the keywords stored in the keyword storage unit, and specifies one category corresponding the extracted keywords when extracting a keyword which was classified into a plurality of categories based on a position thereof and relationships to other words in the text information; a schedule information creation unit which creates new schedule information or revised schedule information which causes schedule information stored in the schedule storage unit to be updated, based on the keywords extracted by the keyword extraction unit and the categories of the extracted keywords; and a schedule updating unit that stores the new schedule information into the schedule storage unit, and updates the schedule information stored in the schedule storage unit with the revised schedule information.