An optical tomographic imaging apparatus includes a first lens having a first focal length, a second lens having a second focal length longer that the first focal length, a scanning unit disposed at a focal position of the second lens, and an optical path branching unit disposed between the first and second lenses. An observation optical path located on a transmission optical path of the optical path branching unit, and an optical path of measurement light located on a reflection optical path of the optical path branching unit. The second lens is disposed on the optical path of the measurement light between the first lens and the scanning unit, such that an angle at which the measurement light scanned by the scanning unit is incident on the optical path branching unit is maintained substantially unchanged during scanning.