A lighting system for a vehicle comprising: a main light (34, 35), an extension located between a reflector (41, 47) for the main light (34, 35) and an outer lens, a light guide member located in the vicinity of the extension, a light source for the light guide member, which is separate from a light source (40, 46) for the main light (34, 35) provided in the main light (34, 35), a light incident section provided in the light guide member for admitting light from the light source into the light guide member, and a driver for the light guide member for adjusting power supply amount to the light source for the light guide member; the light incident section and the driver for the light guide member are arranged in such a position as to be covered by the extension when viewed from the front.; the light guide member is fixedly attached to the extension, and the light source for the light guide member is fixedly attached to at least one of the extension and the light guide member; the light source for the light guide member and the driver for the light guide member are provided on a common base plate, and the base plate is fixedly supported on at least one of the extension and the light guide member; characterized in the lighting system, further comprising a lead wire (75, 76) being led into the housing from a back wall of the housing so as to supply electric power to the driver for the light guide member, wherein the lead wire (75, 76) is formed with a curved portion (75a, 76a) bulging forwardly in front of the back wall and is connected to the base plate, and a regulation plate section being provided at a laterally outer end of the extension so as to regulate laterally inward displacement of the curved portion (75a, 76a) within the housing; and further comprising an adjustment support section which allows the reflector (41, 47) to be supported in the housing in such a manner as to make it possible to adjust an optical axis of the main light (34, 35), wherein the curved portion (75a, 76a) and the adjustment support section are arranged laterally side by side and in close vicinity to each other, and the regulation plate section is located laterally between the curved portion (75a, 76a) and the adjustment support section. a main light (34, 35), an extension located between a reflector (41, 47) for the main light (34, 35) and an outer lens, a light guide member located in the vicinity of the extension, a light source for the light guide member, which is separate from a light source (40, 46) for the main light (34, 35) provided in the main light (34, 35), a light incident section provided in the light guide member for admitting light from the light source into the light guide member, and a driver for the light guide member for adjusting power supply amount to the light source for the light guide member; the light incident section and the driver for the light guide member are arranged in such a position as to be covered by the extension when viewed from the front.; the light guide member is fixedly attached to the extension, and the light source for the light guide member is fixedly attached to at least one of the extension and the light guide member; the light source for the light guide member and the driver for the light guide member are provided on a common base plate, and the base plate is fixedly supported on at least one of the extension and the light guide member; characterized in the lighting system, further comprising a lead wire (75, 76) being led into the housing from a back wall of the housing so as to supply electric power to the driver for the light guide member, wherein the lead wire (75, 76) is formed with a curved portion (75a, 76a) bulging forwardly in front of the back wall and is connected to the base plate, and a regulation plate section being provided at a laterally outer end of the extension so as to regulate laterally inward displacement of the curved portion (75a, 76a) within the housing; and further comprising an adjustment support section which allows the reflector (41, 47) to be supported in the housing in such a manner as to make it possible to adjust an optical axis of the main light (34, 35), wherein the curved portion (75a, 76a) and the adjustment support section are arranged laterally side by side and in close vicinity to each other, and the regulation plate section is located laterally between the curved portion (75a, 76a) and the adjustment support section.