1. An information output device for outputting complementary information related to a document obtained by character recognition for an image, comprising: an expression extraction unit for extracting an expression, for which complementary information can be outputted, from the document; an expression judgment unit for judging whether a character or a symbol adjacent to a beginning or an end of the expression extracted by the expression extraction unit is a predetermined character or symbol or not; a complementary output unit for outputting complementary information related to the extracted expression when the expression judgment unit judges that the character or symbol adjacent to a beginning or an end of the extracted expression is not the predetermined character or symbol; and an output skip unit for skipping output of complementary information related to the extracted expression when the expression judgment unit judges that the character or symbol adjacent to a beginning or an end of the extracted expression is the predetermined character or symbol.