PURPOSE: To perform character processing fast even by a system with a small- capacity memory by redisplaying a character pattern by utilizing a character pattern consisting of dots which are displayed on a display screen once.

CONSTITUTION: On the basis of vector data, a character pattern is generated for an optional character input, and the generated character pattern is expanded in a bit map memory 2. According to a screen format which is previously held in the system, the character pattern of the dots expanded in the bit map memory 2 is outputted on the display screen 7, and the character code and character pattern information of the outputted character pattern are recorded in an output recording table on a hard disk 3. When a character recorded in the output recording table is outputted thereafter, its dot pattern is copied and moved from on the bit map memory corresponding to an output screen by referring to the output recording table, so that the pattern is expanded in the bit map memory 2 and outputted to the display screen.