To provide an illuminator for a shelf of a showcase, wherein an attachment structure is improved so that a fluorescent lamp can be easily fitted to a lower surface side of a merchandise display shelf without using a conventional lamp holder.

The illuminator for shelf of a showcase, which has a linear fluorescent lamp 6 fitted on a lower surface of merchandise display shelves 5 placed on upper and lower shelves in a main body case. The fluorescent lamp is covered with a protection tube 8 made of transparent resin, a socket is connected to metal caps 6a at both ends, and is fixed and supported at a prescribed position. The fluorescent lamp 6 is inserted into the protection tube 8, and then the protection tube is placed between a projection bracket 5b which is also used as a reinforcement material laid on a lower surface of a shelf plate along a longitudinal direction of the merchandise display shelf and a back end edge part 7a of a shelf tag mole 7 fitted to a front edge of the shelf plate, and is fixed. To be more specific, the protection tube 8 is a circular tube which has a diameter being a size larger than that of the fluorescent light 6 and is elastically deformable. A diameter gap (d) between the bracket 5b provided on the lower surface of the commodity display rack and the back end edge part 7a of the rack tag mole 7 is set narrower than a tube diameter of the protection tube, and the fluorescent lamp 6 is clamped and fixed at a fixed position by using elasticity of the protection tube 8.