The illumination device receives a first light with a first light receiving sensitivity and outputs a first light detection signal while receiving a first light and a light source unit that sequentially switches and generates the first light and the second light. A light receiving unit that receives the second light with the second light receiving sensitivity and outputs a second light detection signal, and multiplies the first light detection signal by a coefficient set according to the first light receiving sensitivity. A multiplier for generating a first multiplication signal obtained and a second multiplication signal obtained by multiplying the second photodetection signal by a coefficient set according to the second light receiving sensitivity； An integration unit that integrates at least one of the first and second multiplication signals in a predetermined period, a determination unit that determines whether the integration result exceeds a threshold for determining the state of the light source unit, and a determination And a controller that controls at least one of the first and second light sources based on the result. .照明装置は、第１の光と第２の光とを順次切替えて発生させる光源部と、第１の光を第１の受光感度で受光して第１の光検出信号を出力するとともに、第２の光を第２の受光感度で受光して第２の光検出信号を出力する受光部と、第１の光検出信号に対して第１の受光感度に応じて設定された係数を乗じて得られる第１の乗算信号と、第２の光検出信号に対して第２の受光感度に応じて設定された係数を乗じて得られる第２の乗算信号と、を生成する乗算部と、第１及び第２の乗算信号のうちの少なくとも一方を所定の期間において積算する積算部と、積算結果が光源部の状態を判定するための閾値を超えているか否かを判定する判定部と、判定結果に基づいて第１及び第２の光源のうちの少なくとも一方の光源を制御する制御部と、を有する。
