A light source unit is provided with a first light source, a second light source, and a third light source that emit red light, green light, and blue light, respectively, as illumination light. A light source controller controls emission timing of the illumination light to make emission start timing or emission end timing of the first, second, and third light the same and makes an emission period of the red light longer than an emission period of each of the green light and the blue light. An image sensor is capable of separately receiving light of each color reflected from an object of interest irradiated with the illumination light and capable of separately changing a light-receiving period of the light of each color. An imaging controller makes the light-receiving period of at least the red light coincide with the emission period of the red light.