An illuminator includes a light source apparatus including a red solid-state light source unit that emits red light, a green solid-state light source unit that emits green light, and a blue solid-state light source unit that emits blue light, a light combining system that combines the red light, the green light, and the blue light to generate illumination light and emits the illumination light in a first direction, a focusing lens on which the illumination light emitted from the light combining system is incident, a diffuser disposed on the light exiting side of the focusing lens, and an adjustment lens that is located between the green solid-state light source unit and the light combining system and adjusts the position where the green light is focused.