The invention relates to a lighting device (100) for a motor vehicle headlight, comprising a number of light sources (1), at least one attachment optical unit (2), having a light entrance surface (2a) and a light exit surface (2b), wherein the at least one attachment optical unit (2) comprises a plurality of light-guiding bodies (3), and wherein each light-guiding body (3) has a light entrance surface (3a), into which in each case at least one light source (1) feeds light, and wherein the light-guiding bodies (3) lead into the common light exit surface (2b). According to the invention, at least one, preferably exactly one, position holder (4) is provided, by means of which the light entrance surfaces (3a) of the light-guiding bodies (3) of the at least one attachment optical unit (2) are held in position in relation to the light sources (1). Alternatively or additionally, provision can be made for the light exit surface (2b) of the at least one attachment optical unit (2) to be provided with a transparent light plate (5) for the dimensional stabilization of the at least one attachment optical unit (2).