To more simply detect a state of consciousness of an occupant, and also perform the lighting that meets the state of consciousness of the occupant using an existing interior light.

A cabin lighting system includes an interior light 4 on a vehicle roof part 3, and lights up the periphery of a driver's seat 5 with light from the interior light 4. A wristwatch type pulse sensor 6 is put on a driver D, and the pulse of the driver D is measured with the pulse sensor 6, and a measurement signal is transmitted to a control unit of the interior light 4. The control unit decides a state of consciousness of the driver D on the basis of the pulse measurement value, and controls the dimming of the interior light 4 such that illumination light of color of the driver's preference is generated when in a comfortable state, rest light is generated when in an excited state, awaking light is generated when in a doze state, and warning light is generated when in a slump state.