To provide a leasing contract system which increases leasing contracting customers.

This leasing contract system comprises: an existing equipment information receiving means for receiving existing equipment information on an existing water heater currently used by a customer; a current value calculation means for calculating a current value of an existing equipment, based on the existing equipment information; and a leasing condition calculation means for calculating a current purchase price at the time of purchasing the existing equipment so as to make the leasing contract for the existing equipment under a current state and a leasing fee at the time of making the leasing contract for the existing equipment for a predetermined leasing period, based on the current value of the existing equipment. The system also comprises a leasing contract means for accepting application from the customer to make the leasing contract with the current price and the above leasing fee and for concluding the leasing contract.