An OCT signal processing apparatus includes: a OCT signal receiver configured to receive a plurality of OCT signals detected by an OCT device based on measurement light radiated to a test substance and reference light； a display； a controller configured to: processes the plurality of OCT signals received by the OCT signal receiver to obtain 3-dimensional motion contrast data； extract depth region data from the 3-dimensional motion contrast data, the depth region data representing motion contrast data in a depth region of a part of the test substance； and display, on the display, a confirmation screen including the motion contrast image based on the depth region data to confirm quality of 3-dimensional motion contrast data obtained by processing the plurality of OCT signals which are temporally different from each other in the same region of the test substance.
