To provide a house lease and sales system, capable of easily acquiring the asset management state of a seller side while supporting house purchase of a purchase applicant.

In this house lease and sales system, a house lease agreement valid for a fixed period with a home purchase right to take the amount of the sales price of a dwelling house minus, for example, 55% of the total payment amount of rent as the assignment price of the dwelling house, its release condition and an interim registration permission condition is established with a purchase applicant of the dwelling house who desires to purchase the dwelling house and continues payment of the rent by a home lease and sales program loaded on a seller computer, and the dwelling house is assigned to the purchase applicant by execution of the dwelling house purchase right. When the dwelling house purchase right is not executed for a fixed period, the house lease agreement is extinguished and returned to a general lease agreement.