To provide an on-vehicle vehicle recognition device and a vehicular illumination control device enhancing the detection performance of a tail lamp of a preceding vehicle and a headlight of an oncoming vehicle by a novel constitution.

An image in front of a vehicle is picked up by an on-vehicle image sensor. The light in front of a vehicle is dispersed by a prism 12. In a microprocessor, at least the spectral pattern indicating the relationship between the wavelength of the light from a tail lamp of a light source of a preceding vehicle and the intensity at the wavelength, and the spectral pattern indicating the relationship between the wavelength of the light from the headlight as a light source of an oncoming vehicle and the intensity at the wavelength are stored, and the spectrum of the light in front of the vehicle dispersed by the prism 12 and detected by an image pickup element 10 of the on-vehicle image sensor, is collated with the stored spectral pattern to identify the light source.