A road-surface-detection device (100, 100a, 100b, 200) mountable on a vehicle, the road-surface-detection device (100, 100a, 100b, 200) comprising: a light source configured to emit, to a road surface, light of a plurality of different wavelengths in a visible light wavelength range; a first and a second detector (81, 82), wherein, with the visible light wavelength range being divided into three ranges of a short-wavelength range, a middle-wavelength range, and a long-wavelength range depending on a wavelength, the first detector includes a first filter configured to pass light of the short-wavelength range or the middle-wavelength range, and the second detector includes a second filter configured to pass light from the long wavelength range to a near-infrared wavelength range, and wherein each detector further comprises a corresponding light-receiving device (81b, 82b), the detectors being configured to detect reflection intensities of reflected light having the plurality of different wavelengths, the reflected light being light emitted from the light source and reflected on the road surface; and a road surface determiner configured to determine a type of the road surface, based on the reflection intensities of the reflected light having the plurality of different wavelengths and detected by the detectors (81, 82), characterized in that the road surface determiner is configured to perform a comparison on each of the reflection intensities of the reflected light having the plurality of wavelengths and detected by the detectors (81, 82) with a respective threshold, wherein the road surface determiner is further configured to determine a type of the road surface based on the comparison. a light source configured to emit, to a road surface, light of a plurality of different wavelengths in a visible light wavelength range; a first and a second detector (81, 82), wherein, with the visible light wavelength range being divided into three ranges of a short-wavelength range, a middle-wavelength range, and a long-wavelength range depending on a wavelength, the first detector includes a first filter configured to pass light of the short-wavelength range or the middle-wavelength range, and the second detector includes a second filter configured to pass light from the long wavelength range to a near-infrared wavelength range, and wherein each detector further comprises a corresponding light-receiving device (81b, 82b), the detectors being configured to detect reflection intensities of reflected light having the plurality of different wavelengths, the reflected light being light emitted from the light source and reflected on the road surface; and a road surface determiner configured to determine a type of the road surface, based on the reflection intensities of the reflected light having the plurality of different wavelengths and detected by the detectors (81, 82), characterized in that the road surface determiner is configured to perform a comparison on each of the reflection intensities of the reflected light having the plurality of wavelengths and detected by the detectors (81, 82) with a respective threshold, wherein the road surface determiner is further configured to determine a type of the road surface based on the comparison.