1. A visibility support apparatus comprising: a light source unit configured to illuminate an object with light in one of a plurality of wavelength bands with different peak wavelengths while sequentially switching the wavelength band of the light among the plurality of wavelength bands; a light receiving unit configured to receive reflected light from the object to generate a signal for an image for each of the plurality of wavelength bands thereby generating a series of images corresponding to the plurality of wavelength bands; a wavelength selecting unit configured to compare signal intensities of pixels with each other in at least one image, set a set of those of pixels with comparable signal intensities which define the largest occupied area to be a reference area and set the pixels not included in the reference area to be identification target pixels, and for each of the identification target pixels, compare a value of the pixel in the image for each wavelength band with a pixel value of the reference area to select, among the plurality of wavelength bands, at least two wavelength bands which are effective for detection of the object at each of the identification target pixels; and a display unit configured to classify the identification target pixels into groups based on a combination of a plurality of wavelength bands selected by the wavelength selecting unit for each identification target pixel such that identification target pixels corresponding to the same combination of the selected wavelength bands belong to the same group, and display an image in which the object is distinguishably shown based on the result of the classification such that identification target pixels of one group are distinguished from identification target pixels of another group.