Abstract: A vehicle auxiliary apparatus and a vehicle auxiliary method are provided. The vehicle auxiliary apparatus includes: a first optical sensor disposed on a first side in a moving direction of a vehicle, a second optical sensor disposed on a second side different from the first side in the moving direction of the vehicle, a projection system, and a processor. The processor is configured to measure a first vehicle speed of a first moving vehicle other than the vehicle through the first optical sensor, measure a second vehicle speed of a second moving vehicle other than the vehicle through the second optical sensor, and control the projection system to perform a warning projection within a projection range based on the first vehicle speed, the second vehicle speed, and a vehicle speed of the vehicle.