1. A system for extracting analogous queries, the system comprising: a database storage to store a plurality of databases; and a search server coupled to the database storage, the search server being configured to: create a per-user search query database in the database storage by reading search queries input by users from a search log database in the database storage that contains user device identifiers, search queries input from user devices, and information about time when the users request a search; create a per-user query pair database in the database storage by extracting from the per-user search query database permutations of different two search queries among search queries input by a specific user; read query pairs having a specific query in the per-user query pair database, and create analogous queries by extracting counterparts of the specific query from the query pairs; calculate a conditional probability D of the specific query with regard to each query pair, the conditional probability D comprising: 
 D=P ( A∩B )/ P ( A ) in which P(A) represents a number of user identifiers having a first search query A, and P(A∩B) represents a number of user identifiers having the first search query A and a second search query B, and provide analogous queries in response to a search request for the specific query; and select query pairs having the conditional probability D greater than a given value, extract all counterparts of the specific query from the selected query pairs, and provide the extracted queries as the analogous queries.