The present invention provides a paper sheet recognizing apparatus for recognizing paper sheets having different sizes and colors for each type, by using a sensing unit including a line sensor that detects a light quantity of reflected light or transmitted light obtained by irradiating a paper sheet being transported with a plurality of lights having different source wavelengths. The apparatus includes a storing unit that stores therein reference size data and reference light quantity data generated beforehand for each type of paper sheets to be recognition candidates; a first determining unit that selects a recognition target type from the recognition candidates based on detected size data of the paper sheet detected by the sensing unit and the reference size data; and a second determining unit that determines a type of the paper sheet by comparing detected light quantity data of the paper sheet detected by the line sensor with the reference light quantity data of the recognition target type.