To secure the electric connection between a lead and a bus bar at low costs without being subject to limitations caused by differences between vehicle models on which light emitting element modules are mounted.

Conductive bus bars 3, 4 and at least one light emitting element unit 10 are disposed on an insulative base 2. The light emitting element unit 10 includes a housing 11 which houses a semiconductor light emitting element 16. Leads 12, 13 electrically connected with the semiconductor light emitting element 16 extend from the housing 11. The leads 12, 13 are respectively welded to the bus bars 3, 4. At least one positioning member 5 is provided for each light emitting element unit 10 at the base 2 and is engaged with at least one of the housing 11 and the leads 12, 13.