A light source (2) having a plurality of LEDs (4) and a photodetector (3) for detecting the intensity of light emitted from each of the plurality of LEDs (4) as a light intensity distribution of light emitted from the light source (2). And the current that drives each of the plurality of LEDs (4) is controlled so that the intensity of the light emitted by each of the plurality of LEDs (4) detected by the photodetector (3) falls within a predetermined range. A light intensity distribution control circuit (6).複数のＬＥＤ（４）を備えた光源（２）と、複数のＬＥＤ（４）のそれぞれが発する光の強度を、光源（２）が発する光の光強度分布として検出する光検出器（３）と、光検出器（３）によって検出された複数のＬＥＤ（４）のそれぞれが発する光の強度が所定の範囲内に収まるように、複数のＬＥＤ（４）のそれぞれを駆動する電流を制御する光強度分布制御回路（６）と、を備える。
