1. A medical image processing apparatus for generating a medical image by using three-dimensional volume data representing a portion in a living body, said apparatus comprising: a volume data obtaining unit which obtains predetermined three-dimensional volume data including a tubular tissue; a region specifying unit which specifies a region including a position on the tubular tissue in the three-dimensional volume data, at each of a plurality of such positions; an extraction unit which extracts information on the tubular tissue in each of the specified regions; and a medical image generating unit which generates a medical image representing the tubular tissue, based on the information extracted by said extraction unit.