An endoscope light source device includes a light source device and a light source controller. A first light and a second light are narrow band light in a blue region. A third light is in a green region. A fourth light is in a red region. A first light amount ratio is a ratio of a sum of the light amounts of the first light and the second light, the light amount of the third light, and the light amount of the fourth light. A second light amount ratio is a light amount ratio of the first light and the second light. The light source controller adjusts the light amount ratio of the first light and the second light to achieve the second light amount ratio so as to adjust the color representation from a yellow region to a red region in an image of an object.