Illumination device for vehicle headlamps, especially for single-track vehicle headlamps, comprising: - an optical unit with at least one light source, said optical unit being configured to form a light distribution with a cut-off line, wherein the light distribution is radiated in a main beam direction, - a shell in which the optical unit is mounted, said shell having a first part-spherical gliding surface and a toothed array, - an adapter with a second part-spherical gliding surface complementary to the first part-spherical gliding surface, wherein the shell engages with the adapter so as the first and second part-spherical gliding surfaces can glide on one another, wherein the adapter is mounted on a mount, and - a first adjusting mechanism for rotating the optical unit around a first axis, wherein the first axis is oriented parallel to the main beam direction, said first adjusting mechanism comprising a motor with a gear wheel element, said motor is attached to the mount and configured to generate an angular motion of the gear wheel element along a second axis, wherein the gear wheel element is configured to engage with the toothed array of the shell in order to transmit the angular motion of the gear wheel element to an angular movement of the shell and the optical unit around the first axis, wherein the illumination device comprises a second adjusting mechanism for tilting the optical unit around a third axis, said second adjusting mechanism comprising a linear drive with a transmission element, said linear drive is attached to the mount and configured to generate an angular motion of the transmission element around a fourth axis, wherein the transmission element is configured to engage with the shell or the optical unit in order to convert the angular motion of the transmission element around the fourth axis into an angular motion of the shell and the optical unit around the third axis, and wherein the gear wheel element stays in position along the second axis, and wherein the second axis and the fourth axis are parallel to the first axis. - an optical unit with at least one light source, said optical unit being configured to form a light distribution with a cut-off line, wherein the light distribution is radiated in a main beam direction, - a shell in which the optical unit is mounted, said shell having a first part-spherical gliding surface and a toothed array, - an adapter with a second part-spherical gliding surface complementary to the first part-spherical gliding surface, wherein the shell engages with the adapter so as the first and second part-spherical gliding surfaces can glide on one another, wherein the adapter is mounted on a mount, and - a first adjusting mechanism for rotating the optical unit around a first axis, wherein the first axis is oriented parallel to the main beam direction, said first adjusting mechanism comprising a motor with a gear wheel element, said motor is attached to the mount and configured to generate an angular motion of the gear wheel element along a second axis, wherein the gear wheel element is configured to engage with the toothed array of the shell in order to transmit the angular motion of the gear wheel element to an angular movement of the shell and the optical unit around the first axis, wherein