To provide a renewal kit for a lighting fixture capable of renewing the lighting fixture irrespective of specifications of existing lighting fixtures and moreover capable of changing a fluorescent lamp to be renewed and installed, and to provide a lighting fixture and a renewal method of the lighting fixture.

An existing reflection plate 18 is removed from an installation surface C such as a ceiling ; an outside member 31 including a driving circuit 34 for lighting a fluorescent lamp is fixed on a surface on an outdoor side of the removed reflection plate 18; an inside member 35 including a socket 36 for fixing the fluorescent lamp is fixed on a surface on an indoor side of the reflection plate 18; the reflection plate 18 on which the outside member 31 and the inside member 35 are fixed is fixed again on the installation surface such as a ceiling; and a reflection plate 38 for renewal is fixed on the inside member 35.