The present invention refers to real estate whether relates to information providing system, more by proper price for the management whether each ball a residential building advertised price, price contract engagement, individual official land priceland minute from price then houses contrast, standard value contrast, by providing individual contrast thread transaction value houses official land price ratio, a warrant of the protected price ball individual contrast thread transaction value and standard value embodiment between real estate whether the number inputted from the user by relates to information providing system.