The present invention relates to a financial support system and a method thereof, the system allowing an agreement in advance with respect to an initial rental fee and a rent increase at the time of a lease contract and a renewal contract, and when a lease contract and renewal date are approaching, allowing for an automatic loan with regard to an initial rent and a rent increase through a financial institution (bank) without a separate act. A financial support system according to an embodiment of the present invention comprises : a lessor terminal or a lessee terminal for providing lease contract related information to a real estate electronic contract system via a wired or wireless network; a real estate electronic contract system for providing lease contract information to a financial support server through a wired or wireless network; a financial support server for analyzing the lease contract related information and requesting a guarantee agency server to issue a letter of guarantee for the principal and interest payment of the lessor through the wired or wireless network when the lease contract and renewal date are approaching; a guarantee agency server for issuing, to the financial institution server via the wired and wireless network, a letter of guarantee for the lessor' s payment of the principal and interest at the request of the financial support server; and a financial institution server for receiving, from the lessor terminal through the wired or wireless network, assurances regarding the return of the principal and interest payment, receiving, from the guarantee agency server through the wired or wireless network, an issue of the letter of guarantee for the lessor' s payment of the principal and interest and remitting loans for the initial rent and the rent increase to the lessor' s account.