To provide a lead stopper structure in an LED lighting system preventing a lead of an LED lamp in a housing body from slipping out of a press-contact connection part of a bus bar in assembling a device cover and avoiding reduction of productivity caused by an increase in the number of assembling steps.

An elastic strip 31 which extends toward the bottom side of the housing body 25 through one side of a shell part 3a of the LED lamp 3 in attaching the device cover 28 to the housing body 25 is provided so as to protrude from the device cover 28 and a guide surface 33 for deflecting and deforming an end 31a of the elastic strip 31 is provided on the bottom of the housing body 25 on the side of the lead 3b of the LED lamp 3 which is in press contact and connected with the bus bar 5 in the housing body 25.