A stereo camera for measuring distance to an object using two images of the object having parallax includes an optical multiplexer to set a length of light path of each of the two images having different spectrum properties and parallax to the same length and to superimpose each of the light paths to one light path; an image capturing element to detect luminance of at least two images having different spectrum properties; an optical device to focus a superimposed image on the image capturing element; and a distance computing unit to compute distance to the object using parallax between the two images.