US Patent 7730050 Information retrieval apparatus

An information retrieval apparatus includes a display which displays document information, an input unit which adds additional information to the document information displayed the display, a first storage which stores mark symbol information specifying a particular symbol used for marking, a detector which detects an input from the input unit and decides whether or not the input additional information is identical to or similar to the mark symbol information stored in the first storage, a second storage which stores the mark symbol information and the additional information which is decided that it is similar to the mark symbol information by the detector, associating with the mark symbol information, and a retrieval unit which retrieves the mark symbol information and the additional information associated with the mark symbol information from the second storage, and a retrieval result by the retrieval unit is displayed on the display.