A document reading apparatus reduces processing time and affords excellent ease of use in reading a slip document to acquire magnetic data and/or image data. As the slip is transported through a transportation path, a magnetic reading unit outputs magnetically read data acquired by reading printed magnetic ink characters from the slip and an optical reading unit outputs image data captured by optically imaging the same slip during the same pass through the transportation path. A parameter may be added to a single-pass read command for selectively specifying magnetic reading only, optical reading only, or both magnetic and optical reading as the type or types of reading of a slip during the single pass through the transportation path. Upon receiving the signal-pass read command with the parameter added thereto, a control unit interprets such command and added parameter by selectively controlling the magnetic and optical reading units to executing only the type or types of reading of the slip specified by the parameter in the single-pass read command.