PURPOSE: To obtain high-resolution data by referring to data of the n-th line and data of the (n+1)th line in the subscanning direction of received data to generate interpolation data between them and interpolating picture element data.

CONSTITUTION: A smoothing part 41 discriminates whether printing is started in a recording part 38 of a facsimile equipment or not. Two-line components of picture data are written in a two-line FIFO 100, and data of the first line is read out from the FIFO 100, and data of the first line and the second line are referred to generate interpolation data. Next, data of the second line is read out from the FIFO 100, and it is discriminated whether picture data of all lines are completely read out or not. If they are not completely read out, picture data of the next line is written in the FIFO 100 from a buffer memory 40, and a program reads out the next line. This operation is repeated till the end of read of picture data of all lines.