In an image processing apparatus, an image obtaining unit obtains, from a vehicular camera, an image captured by the vehicular camera based on a predetermined imaging condition. An image processing unit executes an image-processing task of the image. A histogram generation unit generates a histogram based on the luminance values of the pixels included in the road-surface region in the image. The histogram graphically represents a frequency of each of the luminance values of the pixels included in the road-surface region in the image. A histogram determination unit determines whether the histogram has first and second separate crests. A change unit changes, upon determination that the histogram has first and second separate crests, at least one of 1. The imaging condition of the vehicular camera 2. The image-processing task to be executed by the image processing unit.