PROBLEM TO BE SOLVED : To provide a real estate relevant service proxy management device, system, and method for enabling a proxy manager entrusted for a business from a customer being the receiver of a real estate relevant service and a service providing agent to perform various procedures required for the provision/reception business of a specific service instead of the customer and the service providing agent.SOLUTION : The customer side terminal 31 of a customer 310 who receives real estate relevant service provision, the agent side terminal 41 of a service providing agent 410 who provides the real estate relevant service, and a real estate relevant service proxy management device 11 provided to a proxy manager 110 who performs various procedures necessary for the provision/reception business of a specific service on behalf of the customer and the service providing agent, are connected through a communication line 51 one another. The management device 11 is configured to freely hold customer side information necessary for making a contract over the specific service desired by the customer 310, and to hold the provider side information necessary for making a contract over the service provided by the providing agent 410 and to present the contract contents to the proxy manager 110 when conclusion conditions are satisfied between the customer side information and the agent side information.