A light emission apparatus comprising: a light source including a plurality of light emitting elements including a first light emitting element and a second light emitting element configured to emit a light beam, and a detection element; a first drive unit configured to drive the first light emitting element to emit the light beam; a second drive unit configured to drive the second light emitting element to emit the light beam; and a detection unit (308A, 308B) configured to detect an operating state of the detection element, wherein the first drive unit controls a light amount of the light beam to be emitted by the first light emitting element based on the operating state of the detection element detected by the detection unit, and the second drive unit controls a light amount of the light beam to be emitted by the second light emitting element based on the operating state of the detection element detected by the detection unit, characterized in that the first drive unit supplies a detection current to the detection element to detect the operating state, wherein the detection unit detects, as the operating state, a voltage of the detection element to which the detection current is supplied by the first drive unit, and wherein the first drive unit controls the light amount of the light beam to be emitted by the first light emitting element based on the voltage of the detection element detected by the detection unit, and the second drive unit controls the light amount of the light beam to be emitted by the second light emitting element based on the voltage of the detection element detected by the detection unit. a light source including a plurality of light emitting elements including a first light emitting element and a second light emitting element configured to emit a light beam, and a detection element; a first drive unit configured to drive the first light emitting element to emit the light beam; a second drive unit configured to drive the second light emitting element to emit the light beam; and a detection unit (308A, 308B) configured to detect an operating state of the detection element, wherein the first drive unit controls a light amount of the light beam to be emitted by the first light emitting element based on the operating state of the detection element detected by the detection unit, and the second drive unit controls a light amount of the light beam to be emitted by the second light emitting element based on the operating state of the detection element detected by the detection unit, characterized in that the first drive unit supplies a detection current to the detection element to detect the operating state, wherein the detection unit detects, as the operating state, a voltage of the detection element to which the detection current is supplied by the first drive unit, and wherein the first drive unit controls the light amount of the light beam to be emitted by the first light emitting element based on the voltage of the detection element detected by the detection unit, and the second drive unit controls the light amount of the light beam to be emitted by the second light emitting element based on the voltage of the detection element detected by the detection unit.