In the case that media data containing image information of persons are managed, protection of privacy is realized, and an increase in management costs and a deterioration of operability are suppressed.In a media data processing apparatus into which media data containing at least one image information is inputted so as to produce encrypted media data, the media data processing apparatus is equipped with: biological feature extracting unit 10 for extracting a feature of biological information which is related to at least one person contained in said image information from the media data inputted thereinto; and encrypting process unit 20 for partially, or wholly encrypting the media data based upon the feature extracted by the biological feature extracting unit. A feature parameter of a face of the person contained in the media data is utilized.