PROBLEM TO BE SOLVED : To provide a guarantee charge rate calculation system capable of calculating an appropriate guarantee charge rate.SOLUTION : This guarantee charge rate calculation system for calculating a guarantee charge rate of a real estate loan the guarantee charge rate of which is fluctuated after execution of the loan comprises : an attribute information database storing information related to an applicant of the loan for every factor which needs a change in guarantee charge rate; a determination database preliminarily storing a determination condition for determining whether the change in guarantee charge rate is needed for every factor needing the change in guarantee charge rate; an information collection means collecting information for the applicant of the loan for every factor needing the change in guarantee charge rate and storing it in the attribute information database; and a calculation means calculating and outputting, at predetermined intervals, a new guarantee charge rate by use of a predetermined calculation equation based on information needing the change in guarantee charge rate in reference to the information stored in the attribute information database and the determination condition stored in the determination database.COPYRIGHT : (C)2006, JPO&NCIPI