An optical tomographic imaging apparatus includes a first lens, an optical path branching unit, a second lens and a scanning unit disposed on an optical path of measurement light with which an object to be examined is irradiated. The second lens and the scanning unit are disposed in such a manner that an angle at which the measurement light scanned by the scanning unit is incident on the optical path branching unit satisfies a wavelength separation characteristic of 90% or higher at a wavelength of observation light of the object to be examined in a wavelength band of the measurement light.