PROBLEM TO BE SOLVED : To provide a management system for real estate rental operation capable of managing easily operations of real estate.SOLUTION : The system comprises an input part 2 to input data, a display part 3 to display characters, images, etc., a pay-in reserve processing part 4 to decide to which billing item the money paid-in from a customer should be reserved, a demand processing part 5 to demand for payment to the customer when the customer has not paid against the claim, a response processing part 6 for inquiry about pay-in from customer to perform check processing of pay-in state corresponding to inquiries from customers about pay-in, a DB 7 to store data on parking areas, a DB 8 to store data on rooms and the areas, a DB 9 to store data on contractors tenants, etc., a DB 10 to store data on claims to rental fees, a DB 11 to store data on rent and a DB 12 to store data on names of contractors, etc.