A character string anonymizing apparatus classifies each of a plurality of pieces of text data, each including a character string, into a plurality of kinds of data in accordance with a classification condition, extracts a plurality of words included in each of the plurality of pieces of text data (hereinafter, referred to as linked data) classified into the same kind by the classification, extracts, among word sets including one or more of the extracted words, a word set in which the number of pieces of linked data including all words forming each of the word sets is greater than or equal to a threshold, and anonymizes, among words included in a character string included in each of the plurality of pieces of text data, a word matching at least some of the extracted words and not matching words forming the extracted word set.