1. An image information summary apparatus for extracting one piece or plural pieces of partial image information which is a portion of the input image information from the input image information and generating the summary information in which a time length of the image information is contracted on the basis of the extracted partial image information, comprising: an obtaining device which obtains the preliminary announcement information which has been generated in advance and in which characteristic portions in the input image information are continuously connected; a detecting device which detects the same partial information which is the same image information as the characteristic portion which constitutes the preliminary announcement information from the input image information; a decision device which decides the partial image information to be extracted on the basis of the detected same partial information; and a generating device which generates the summary information by extracting the decided partial image information from the input image information.