An adjustment device for a vehicle light emitting module, the adjustment device comprising a light emitter support unit and an adjustment conversion unit, wherein the light emitter support unit comprises a rotatable light emitter bracket configured to support a light emitter, and the adjustment conversion unit comprises an adjustment conversion structure and a translation member provided with a receiving part forming a receiving hole, and a first support part of the light emitter bracket is moveably received in the receiving part, wherein, the adjustment conversion structure comprises an adjustment gear member, and wherein the adjustment conversion unit is configured to convert a rotation movement of the gear member into a translation movement of the translation member, thereby the translation movement of the translation member causing rotation of the light emitter bracket, wherein, the first support part is in contact with an annular section of an inner wall of the receiving part, wherein, the first support part: - either is columnar, having a constant cross-section, the annular section of the inner wall of the receiving part having a narrowing portion in a longitudinal direction of the receiving part, and a cross-sectional size of the narrowing portion matches a cross-sectional size of the first support part, so that the first support part is in contact with the inner wall of the receiving part only at the annular section of the inner wall, - or has a spherical section having a diameter greater than horizontal dimensions of other sections of the first support part when mounted on a vehicle, the receiving hole of the receiving part being a columnar hole of a constant cross section and of a diameter that matches a diameter of the spherical section, and wherein, there is a linear contact between the first support part and the inner wall of the receiving part. wherein the light emitter support unit comprises a rotatable light emitter bracket configured to support a light emitter, and the adjustment conversion unit comprises an adjustment conversion structure and a translation member provided with a receiving part forming a receiving hole, and a first support part of the light emitter bracket is moveably received in the receiving part, wherein, the adjustment conversion structure comprises an adjustment gear member, and wherein the adjustment conversion unit is configured to convert a rotation movement of the gear member into a translation movement of the translation member, thereby the translation movement of the translation member causing rotation of the light emitter bracket, wherein, the first support part is in contact with an annular section of an inner wall of the receiving part, wherein, the first support part: - either is columnar, having a constant cross-section, the annular section of the inner wall of the receiving part having a narrowing portion in a longitudinal direction of the receiving part, and a cross-sectional size of the narrowing portion matches a cross-sectional size of the first support part, so that the first support part is in contact with the inner wall of the receiving part only at the annular section of the inner wall, - or has a spherical section having a diameter greater than horizontal dimensions of other sections of the first support part when mounted on a vehicle, the receiving hole of the receiving part being a columnar hole of a constant cross section and of a diameter that matches a diameter of the spherical section, - either is columnar, having a constant cross-section, the annular section of the inner wall of the receiving part having a narrowing portion in a longitudinal direction of the receiving part, and a cross-sectional size of the narrowing portion matches a cross-sectional size of the first support part, so that the first support part is in contact with the inner wall of the receiving part only at the annular section of the inner wall, - or has a spherical section having a diameter greater than horizontal dimensions of other sections of the first support part when mounted on a vehicle, the receiving hole of the receiving part being a columnar hole of a constant cross section and of a diameter that matches a diameter of the spherical section, and wherein, there is a linear contact between the first support part and the inner wall of the receiving part.