The present invention relates to a method for a real estate transaction management using customer authentication, which comprises a first step of inputting member information; a second step of connecting to a real estate information management server; a third step of customer authentication for verifying a customer' s real name; a fourth step of querying and retrieving; a fifth step of storing information on a real estate that the customer queried, and the method is characterized in that information of the customer and a history of the real estate retrieved by the customer' s request that is stored in the real estate management server is transmitted from the real estate management server to a portable terminal right after the third step, and displayed in the portable terminal if the first, second and third steps are executed again by a customer' s request. According to the present invention, a real estate agent can discretionally determine whether or not to open detail information of a real estate on sale based on a query history of the real estate through a customer authentication, whereby information on offerings can be protected against camouflage customers who wants to surreptitiously get the information on offerings provided from other agents, and providing alternatives for ensuring fair competition.[Reference numerals] (S100) Step of inputting member information; (S200) Step of connection; (S300) Step of customer authentication; (S400) Step of querying and retrieving; (S500) Step of storing real estate information customer queriedCOPYRIGHT KIPO 2014