PURPOSE: To evade the deterioration of image quality, which is caused by executing large variable power being below 50% or below to a binary image which is adaptively processed.

CONSTITUTION: A scanner 1 executes the two times of scannings and transmits multi-level image data of unmagnification (100%) and multi-level image data which is executed 50% variable power to an adaptive processing part 2. The adaptive processing part 2 respectively binarizes a character and a pattern which are image area-separated and they are stored in a storing part 3. The binary image of the storing part 3 is selected in accordance with resolving power at transmission/reception sides and, moreover, variable power is processed in a binary image variable power part 4 in accordance with the document size of the transmission side and the printer size of the reception side.