A vehicular illumination device includes a light distribution control unit, a determination unit and a control unit. The light distribution control unit performs an alteration control of a vehicular illumination unit so as to alter a light distribution with respect to an illumination object detected by a detection unit. When the illumination object ceases to be detected, the determination unit determines whether or not there is a need to maintain the alteration control in a current state. When it is determined that there is a need to maintain the alteration control in the current state, the control unit controls the light distribution control unit so as to maintain the alteration control in the current state.