PROBLEM TO BE SOLVED: To provide a light source device for an endoscope, an endoscope system, and an operation method thereof capable of improving quality of a red image, and acquiring a high quality observation image by color emphasis processing.SOLUTION: A light source part includes a first light source for emitting red light LR, a second light source for emitting green light LG, and a third light source for emitting blue light LB, and emits the red light LR, the green light LG, and the blue light LB as illumination light respectively. A light source control part controls a light emitting timing of the illumination light to cause the light emission start timings or the light emission finishing timings of the red light LR, the green light LG, and the blue light LB to be the same, and to cause the light emission time of the red light LR to be longer than the emission time of the green light LG and the blue light LB. An imaging device can receive the return light from an observation target for each color to which the illumination light is irradiated, and the light receiving period can be changed for each color. An imaging control part causes the light receiving period for at least the red light LR of the imaging device to coincide with the light emission period of the red light LR.SELECTED DRAWING: Figure 7【課題】赤色画像の画質を向上させ、色彩強調処理により高画質な観察画像を得ることを可能とする内視鏡用光源装置、内視鏡システム及びその作動方法を提供する。【解決手段】光源部は、赤色光ＬＲを発する第１光源と、緑色光ＬＧを発する第２光源と、青色光ＬＢを発する第３光源とを備え、赤色光ＬＲ、緑色光ＬＧ、青色光ＬＢをそれぞれ照明光として発する。光源制御部は、照明光の発光タイミングを制御して、赤色光ＬＲ、緑色光ＬＧ、青色光ＬＢの発光開始タイミングまたは発光終了タイミングを同時とし、かつ、赤色光ＬＲの発光時間を緑色光ＬＧ及び青色光ＬＢの発光時間より長くする。撮像素子は、照明光が照射された観察対象からの戻り光を、色ごとに受光可能で、かつ色ごとに受光期間が変更可能である。撮像制御部は、撮像素子の少なくとも赤色光ＬＲに対する受光期間を赤色光ＬＲの発光期間に一致させる。【選択図】図７
