To add a proper mark to an object designated by a user without imposing any complicate operation on the user.

This information processor is provided with an electronic contents storing part 106 for storing electronic contents, an electronic contents display processing part 107 for displaying the electronic contents, an object recognizing part 108 for recognizing a designated object among objects included in the displayed electronic contents, an object group specifying part 109 for specifying the object group belonging to the recognized objects, a mark contents extracting part 112 for extracting information showing mark contents for the specified object group and a mark adding part 113 for adding the mark to the object recognized by the object recognizing part 108 based on the mark contents extracted by the mark contents extracting part 112.