An object detector configured to scan a plurality of areas in a scanning direction, the object detector comprising: a light-emitting system including a light source that includes a plurality of light-emitting elements (LE) disposed in one-axis direction perpendicular to the scanning direction, the light-emitting system configured to emit light; and a light-receiving system configured to receive the light emitted from the light-emitting system and reflected by an object; wherein the plurality of light-emitting elements (LE) are configured to emit a plurality of light beams to a plurality of areas (IR) differing in position in the one-axis direction, and wherein an amount of light illuminating some of the plurality of areas (IR) is different from an amount of light illuminating other area other than the some of the plurality of areas (IR) wherein the light-emitting system further includes an optical system configured to guide the plurality of light beams emitted from the plurality of light-emitting elements (LE) to the plurality of areas (IR), a path of each light beam defining an optical path associated with the corresponding light-emitting element (LE), wherein the plurality of light emitting elements (LE) includes a first light emitting element and a second light emitting element, the second light emitting element disposed further from a center of the light source in the one-axis direction than the first light emitting element, characterised in that the optical system is configured such that light loss is greater in the optical path associated with the second light emitting element than in the optical path associated with the first light emitting element. a light-emitting system including a light source that includes a plurality of light-emitting elements (LE) disposed in one-axis direction perpendicular to the scanning direction, the light-emitting system configured to emit light; and a light-receiving system configured to receive the light emitted from the light-emitting system and reflected by an object; wherein the plurality of light-emitting elements (LE) are configured to emit a plurality of light beams to a plurality of areas (IR) differing in position in the one-axis direction, and wherein an amount of light illuminating some of the plurality of areas (IR) is different from an amount of light illuminating other area other than the some of the plurality of areas (IR) wherein the light-emitting system further includes an optical system configured to guide the plurality of light beams emitted from the plurality of light-emitting elements (LE) to the plurality of areas (IR), a path of each light beam defining an optical path associated with the corresponding light-emitting element (LE), wherein the plurality of light emitting elements (LE) includes a first light emitting element and a second light emitting element, the second light emitting element disposed further from a center of the light source in the one-axis direction than the first light emitting element, characterised in that the optical system is configured such that light loss is greater in the optical path associated with the second light emitting element than in the optical path associated with the first light emitting element. <EOS>