PURPOSE: To attain data compression by segmenting a character dot in row or a column direction and specifying a character data with information relating to its start position and consecutive state.

CONSTITUTION: The subject method is provided with a process segmenting a bit map in a row and a column direction at a prescribed pitch with respect to bits constituting a character assigned on an m-row n-column bit map and with a process representing the presence of print dots in each row (column) from a 1st row (column) till a m-th row (column) segmented in the row or column direction in terms of a dot presence data. Moreover, the process giving information relating to the start position of print dots and the continuity of dots with respect to the row (column) where print dots exist is provided. That is, a character is broken down at a prescribed pitch in the horizontal and vertical direction, the section of each row (column) is noticed and the dot start position and the dot consecutive length of the section only where dots exist are taken as a data. Thus, a character font is stored with a few storage capacity and the magnification and the reduction are facilitated.