Abstract: In an MR code expanding apparatus, a reference line processing circuit shifts reference line data bit-serially and at the same time, searches for a color changing point of the reference line data at seven successive picture element positions in parallel. An output data producing circuit produces, bit-serially and in synchronism with the shifting of the reference line data, expanded line data of each picture element corresponding to each reference line picture element arriving at the center of these seven picture element positions. A code analyzing circuit supplies the reference line processing circuit with a signal which designates one of these seven picture element positions at which the color changing point is to be detected. A signal which represents detection of the color changing point at the designated picture element position is used for controlling the state transition of the expanding operation.