1. An apparatus for discriminating document orientation, comprising: separating means for separating entered document image data into a plurality of partial areas; attribute discriminating means for discriminating to which of a plurality of types of attributes each of the plurality of partial areas obtained by said separation processing means corresponds, and assigning the attribute discriminated to each partial area; character orientation discriminating means for discriminating orientation of characters contained in each of the plurality of partial areas obtained by said separating means; selection means for selecting a partial area assigned an attribute of highest priority from among each of the plurality of partial areas; and deciding means for deciding orientation of the document image data based upon the discriminated character orientation of the partial area selected by said selection means.