A diffusion body (10) receives incoming first light (L1) and emits scattered light. The diffusion body (10) has one light-entering surface (10a) through which the first light (L1) enters in a first direction and a first light-emitting surface (10b). The light-entering surface (10a) is formed on an end face of the diffusion body (10). First emitted light (L21) is emitted from the first light-emitting surface (10b). Second emitted light (L22) is emitted from a second light-emitting surface (10c), which is a surface other than the first light-emitting surface (10b) of the diffusion body (10). The intensity of the first emitted light (L21) increases as the emitted direction of the first emitted light (L21) is closer to the first direction. The correlated color temperature of the first light (L1) is lower than the correlated color temperature of the first emitted light (L21) and is higher than the correlated color temperature of the second emitted light (L22).