3. The document editing device according to claim 2 , wherein the control module displays a warning message on the display module if a plurality of character decoration types are set to at least one of the character strings, the character strings being determined by the search to be set with the character decoration type identical to the search-target, and a character decoration type that is incompatible with the conversion character decoration type is included in the plurality of character decoration types.
2. The document editing device according to claim 1 , wherein the control module collectively converts the character decoration type of all character strings, the character strings being determined by the search to be set with the character decoration type identical to the search-target, into a conversion character decoration type specified by an operation of the operation module by the user.