1. An image capturing apparatus for obtaining information regarding a depth of a subject, comprising: an illumination unit operable to cast a first illumination light beam mainly having a first wavelength and a second illumination light beam mainly having a second wavelength and a third wavelength from optically different emission positions onto said subject, said second and third wavelengths being different from said first wavelength; and a depth calculator operable to calculate a depth-direction distance to said subject based on outgoing light beams from said subject.