A reading apparatus configured to read a plurality of colorimetric patches in different colors formed on a paper sheet and trigger patches formed so as to correspond to the colorimetric patches includes: a colorimeter configured to read the colorimetric patches; a trigger sensor configured to read the trigger patches; and a controller configured to control a reading region, wherein the controller has a colorimetry region determination mode in which the reading region is determined and a colorimetry adjustment mode in which the reading region is controlled, and in the colorimetry region determination mode, after the reading regions are set to states where the reading regions are gradually shifted in a reading direction, the reading results for the colorimetric patches are collected and thereafter, a region for which a state consistent with a characteristic of the colorimetric patch has been obtained as the reading result is determined as the reading region.