A vehicle illumination system provided to a vehicle capable of traveling in an automatic driving mode and configured to detect a target object, the vehicle illumination system comprising: a left-side communication support lamp and a right-side communication support lamp configured to emit light toward an outside of the vehicle and arranged to be visually recognized from the front of the vehicle; and an illumination control unit configured to, when the vehicle detects a target object, change an illumination state of at least one of the left-side communication support lamp and the right-side communication support lamp, wherein the illumination control unit is configured to control the illumination state of the left-side communication support lamp and the right-side communication support lamp so that the left-side communication support lamp and the right-side communication support lamp are to function as a turn signal lamp, wherein each of the left-side communication support lamp and the right-side communication support lamp includes a plurality of light-emitting segments (43L, 43R) arranged side by side in a right and left direction of the vehicle, wherein the illumination control unit is configured to change an illumination state of each of the plurality of light-emitting segments (43L, 43R), and wherein the illumination control unit is configured to change the illumination state of at least one of the left-side communication support lamp and the right-side communication support lamp, in correspondence to a relative positional relation between the vehicle and the target object, wherein when the vehicle stops after detecting the target object, the illumination control unit is configured to change the illumination states of at least one of the left-side communication support lamp and the right-side communication support lamp, and characterised in that when the vehicle stops after detecting the target object, the illumination control unit is configured to sequentially change a light-emitting segment, which is to be turned on or turned off, of at least one of the plurality of light-emitting segments (43L, 43R) of the left-side communication support lamp and the right-side communication support lamp, along a movement direction of the target object. a left-side communication support lamp and a right-side communication support lamp configured to emit light toward an outside of the vehicle and arranged to be visually recognized from the front of the vehicle; and an illumination control unit configured to, when the vehicle detects a target object, change an illumination state of at least one of the left-side communication support lamp and the right-side communication support lamp, wherein the illumination control unit is configured to control the illumination state of the left-side communication support lamp and the right-side communication support lamp so that the left-side communication support lamp and the right-side communication support lamp are to function as a turn signal lamp, wherein each of the left-side communication support lamp and the right-side communication support lamp includes a plurality of light-emitting segments (43L, 43R) arranged side by side in a right and left direction of the vehicle, wherein the illumination control unit is configured to change an illumination state of each of the plurality of light-emitting segments (43L, 43R), and wherein the illumination control unit is configured to change the illumination state of at least one of the left-side communication support lamp and the right-side communication support lamp, in correspondence to a relative positional relation between the vehicle and the target object, wherein when the vehicle stops after detecting the target object, the illumination control unit is configured to change the illumination states of at least one of the left-side communication support lamp and the right-side communication support lamp, and characterised in that when the vehicle stops after detecting the target object, the illumination control unit is configured to sequentially change a light-emitting segment, which is to be turned on or turned off, of at least one of the plurality of light-emitting segments (43L, 43R) of the left-side communication support lamp and the right-side communication support lamp, along a movement direction of the target object.