To provide a technique capable of supporting trading of an immovable estate effectively.

A refurbishment plan for a collateral immovable estate is prepared, and a refurbished cost is detected (d in Figure). A sales amount in the refurbished collateral immovable estate is determined to bring an amount provided by subtracting the refurbishment cost from the sales amount into an amount complied with a debtor or more, the collateral immovable estate is sold by the sales amount (g in Figure), and a creditor recovers an active deby from the amount provided by subtracting the refurbishment cost from the sales amount (n in Figure), when sale is materialized (h in Figure).