This is an optical three-dimensional measurement device provided with observation illumination light for illuminating an observation specimen, an object lens for collecting the observation light on the observation specimen and a display unit for displaying an observation image and its measurement result that are obtained via the object lens. The optical three-dimensional measurement device comprises a filter process determination unit for determining a first filter process on the basis of observation conditions used when taking in a three-dimensional image of the observation specimen and a filter process unit for applying the first filter process determined by the filter process determination unit to the measurement image or the measurement result.