A video signal processing apparatus (and method) includes a section determination unit which detects a non-equidistant section having different intervals between a plurality of sample points set for a range from a minimum signal level to a maximum signal level of a video signal to be inputted,correction level holding unit which holds a signal level of a video signal after correction for each sample point as a correction level, and an interpolation computation unit which obtains a signal level of the video signal after correction corresponding to the signal level of the inputted video signal by executing cubic interpolation computation with reference to the correction level held by the correction level holding unit.