A light source unit, comprising: a plurality of light emitting elements disposed with a dispersed pattern in a two-dimensional direction to together form a light emitting element assembly, the light emitting element assembly being configured to emit light to a target; and a light emitting element supporter to support the plurality of light emitting elements of the light emitting element assembly, wherein the light emitting element supporter includes: a single, central ventilating hole at an inner portion of the light emitting element assembly, extended in in the two-dimensional directions, and configured to cause cooling air, supplied from a rear side of the light emitting side of the light emitting element assembly, to pass through the single, central ventilating hole to the light emitting side of the light emitting element assembly; a heat dissipater disposed with the light emitting element supporter at the rear side of the light emitting side of the light emitting element assembly to dissipate heat of the light emitting element assembly, wherein the heat dissipater has a single, central through hole communicable with the single, central ventilating hole of the light emitting element supporter; and an air supply unit disposed at the rear side of the light emitting side of the light emitting element assembly configured to supply cooling air to the single, central ventilating hole via the single, central through hole. a plurality of light emitting elements disposed with a dispersed pattern in a two-dimensional direction to together form a light emitting element assembly, the light emitting element assembly being configured to emit light to a target; and a light emitting element supporter to support the plurality of light emitting elements of the light emitting element assembly, wherein the light emitting element supporter includes: a single, central ventilating hole at an inner portion of the light emitting element assembly, extended in in the two-dimensional directions, and configured to cause cooling air, supplied from a rear side of the light emitting side of the light emitting element assembly, to pass through the single, central ventilating hole to the light emitting side of the light emitting element assembly; a heat dissipater disposed with the light emitting element supporter at the rear side of the light emitting side of the light emitting element assembly to dissipate heat of the light emitting element assembly, wherein the heat dissipater has a single, central through hole communicable with the single, central ventilating hole of the light emitting element supporter; and an air supply unit disposed at the rear side of the light emitting side of the light emitting element assembly configured to supply cooling air to the single, central ventilating hole via the single, central through hole. a single, central ventilating hole at an inner portion of the light emitting element assembly, extended in in the two-dimensional directions, and configured to cause cooling air, supplied from a rear side of the light emitting side of the light emitting element assembly, to pass through the single, central ventilating hole to the light emitting side of the light emitting element assembly; a heat dissipater disposed with the light emitting element supporter at the rear side of the light emitting side of the light emitting element assembly to dissipate heat of the light emitting element assembly, wherein the heat dissipater has a single, central through hole communicable with the single, central ventilating hole of the light emitting element supporter; and an air supply unit disposed at the rear side of the light emitting side of the light emitting element assembly configured to supply cooling air to the single, central ventilating hole via the single, central through hole.