PURPOSE: To absorb non-coincidence of a source document size and to perform output in the same size as the input.

CONSTITUTION: Source document information from a G3 facsimile transmitted to a facsimile adapter is received through a modem 121, converted to code data and stored in a modem buffer 122A by DMA transfer. The code data of the modem buffer 122A are transferred to a DICEP-A (coding/decoding circuit) 122B by PIO transfer, developed into pixel data by being decoded in the DICEP-A 122B and stored in a line buffer 122C. The pixel data stored in the line buffer 122C are stored in a picture element memory 122D which is the common area of the facsimile adapter and transferred to a G4 facsimile by the DMA transfer.