An object of the present invention is to provide an on-vehicle interior illuminating device able to show the light moving with a small number of light sources and to reduce cost. The on-vehicle interior illuminating device includes: a light guide member; one light source unit; the other light source unit; and a control unit. The control unit turns on the other light source unit after turning on the one light source unit, turns off the one light source unit after turning on the other light source unit, and turns off the other light source unit after turning off the one light source unit.