This invention relates to an apparatus for automatically inspecting abnormality in external surface, dirt on the surface, and poor shape of cylindrical objects by using image processing. The apparatus for inspecting the appearance of the cylindrical object according to the present invention comprises: rotating means for rotating the cylindrical object about an axis of the cylindrical object; picking up means for picking up images showing the appearance of the inspected object which are axially and circumferentially divided into a predetermined number; masking window generating means for generating masking windows for masking characters and symbols which are printed on an axially predetermined portion of the divided picked-up images of the inspected object; detecting window generating means for generating detecting windows for extracting portions on the axially predetermined portion of the divided picked-up images of the inspected object on which the characters and symbols are not printed; adding means for adding luminance excluding the luminance of the masking window for divided picked-up images each; and comparing means for comparing the added luminance with a predetermined threshold, wherein a portion where the added luminance exceeds the threshold is judged to be defective.