PROBLEM TO BE SOLVED : To provide an agreement system by a fixed period for a weekly or monthly apartment or the like.SOLUTION : This system is a period subscription system for a rental real estate by a period-fixed rental-house agreement, and is provided with an object database for storing data about rental real estate objects, a rental income database for setting a rental income in each of the rental real estate objects corresponding to a rented period thereof to be stored, a subscription data storage means for storing a subscription data of the each rental real estate object, a period fixing means for storing a period fixing data for settling the subscription period, and a rental income changing means for changing the rental income according to a condition including the period fixing data. The system is provided with at least a function by which the rental income based on a period-fixed agreement is varied by a discount or the like, and by which a subscription data after the subscribed fixed period for every object mentioned above can be stored newly.