A link destination hypertext is acquired of an original anchor present in a processing range in an original hypertext, and link destination anchor information composed of a pair of a link destination anchor character string and a link destination URL is extracted from the link destination hypertext. An original anchor effective range is determined which serves as a candidate character string range to which a new anchor is added in the original hypertext, a character string present in the original anchor effective range is compared with a character string present in the link destination anchor information, new anchor information is generated which is composed of a pair of a matched ranged character string and a new link destination URL, and a new anchor is attached to the matched range character string of the original hypertext, so as to convert the original hypertext to a new hypertext.