An apparatus and method for controlling the taillight of a vehicle are disclosed. The apparatus includes a visible light wireless communication data generation unit, a brightness control unit, a variable pulse position modulation (VPPM) signal generation unit, and a light source. The visible light wireless communication data generation unit generates information about the operation of a vehicle. The brightness control unit generates a brightness control value that is used to control the brightness of a light source installed at the tail of the vehicle. The variable pulse position modulation (VPPM) signal generation unit controls a pulse position and a pulse width within a unit pulse section of a pulse that controls the light source based on the information about the operation of the vehicle and the brightness control value.