An OCT signal processing device has an acquisition unit for acquiring three or more OCT signals being temporally different from each other with respect to the same position on a subject, from an OCT device that detects an OCT signal based on reflection light of measurement light applied to a subject and reference light corresponding to the measurement light, and a calculation unit for calculating motion contrast based on a plurality of OCT signals. The calculation unit selects two or more sets of OCT signals having different time interval between the OCT signals among sets obtained by extracting a plurality of OCT signals out of the three or more OCT signals, and calculates motion contrast for each of the selected two or more sets.
