A single-cluster lamp drive device makes use of a controller to receive video data from a control system and then divides the video data into three sub video data. Next, these three sub video data are simultaneously and repetitively outputted to a digital-to-analog converter in every fixed time interval. Subsequently, the digital-to-analog converter converts these three sub video data to three analog voltages outputted to a voltage-to-current converter. Finally, the voltage-to-current converter converts these three analog voltages to three analog currents for driving light emitting devices to emit light, hence accomplishing voltage-in-current-out driving. The drive device drives a single-cluster lamp composed of one LED or several LEDs to adjust their brightness through current change, thereby coordinating with the control system to produce various color and pattern variations.