There are four types of the Housing Defect Warranty Liability Insurances for existing houses, roughly classified according to the size of remodeling construction and the transaction type. The penetration factors are that some customers understood the benefits of combining insurances with various peripheral measures such as tax incentives And that certain housing businesses used the insurances as a differentiating factor for business. In order to disseminate further in the future, it is necessary to appeal not only to housing businesses but also to customers, and to develop insurance products that the businesses can use easily.