In an apparatus including the detachable unit, when reading individual information of the detachable unit, a first label for generating a reference signal for reading individual information and a second label representing the individual information are arranged on a surface of the detachable unit, with a first label reading unit, the reference signal is generated while reading the first label in a predetermined direction, and with a second label reading unit, the individual information of the detachable unit contained in the second label is read in synchronous with the generated reference signal. Read individual information is stored, and whether a mounted detachable unit is new or used is recognized based on a comparison of individual information read from the detachable unit with stored individual information.