A keyword extracting device which extracts keywords collectively and efficiently while improving descriptive property and reusability of the information for keyword extracting. A text data input inputs a text. A pattern processor carries out matching and replacement of a character string based on a pattern in regular expression or its equivalent. A pattern storage stores at least a keyword component pattern representing a character string capable of being a component of a keyword. A keyword component extractor extracts, as keyword components, all character strings which are matched with a keyword component pattern and are not overlapped with each other by using the pattern processor for a text. A keyword candidate set generator generates a keyword candidate set from each keyword. And, a keyword output outputs each keyword candidate of a keyword candidate set as a keyword.