To provide an economic synergic effect by securing safety in a repair construction of an existing house, improving working efficiency, reexamining the structure of existing foundations, establishing a predetermined strength, and shortening a construction period.

In a first step, a proper foundation of a concrete structure corresponding to a site ground is so integrally constructed that the existing foundations are surrounded or supported while leaving the existing foundations with the columns and bases of the existing house undisturbed. The foundation is continuously formed as far as possible. In a second step, the replacement and the repair of the columns and bases, and the recovering of the levelness of the house which are the main purpose of this house repair are performed by utilizing jacks. In a third step, the treatment of the gap between the foundation and a skeleton portion produced during the operations in the above steps is performed by inserting a liner, and the gap and the liner are fixed with an encased concrete foundation. The construction method is formed mainly of the above three steps.