There are provided an optical tomographic imaging apparatus which detects an amount of movement of an object during imaging to reduce a deformation or a displacement in a depth direction in an acquired image. The apparatus using interference beams obtained by combining each return beam with each reference beam, the return beams being obtained by scanning the object with measuring beams, including: a unit adapted to scan the object with the measuring beams a unit adapted to irradiate the object with the measuring beams such that regions of the object irradiated with each measuring beams are partially overlapped a unit adapted to calculate a positional difference in a depth direction between obtained tomographic images of the overlapped parts of the regions and a unit adapted to compute an amount of movement of the object based on the calculated positional difference in the depth direction.
