PURPOSE: To shorten the processing time greatly as compared with a case wherein a font is specified and then a dot pattern is developed by storing the dot pattern which is estimated to be specified in a state similar to the development.

CONSTITUTION: This image forming device is equipped with a storage means 1 stored with the front which is developed into a dot pattern previously, a developing means 2 which develops the font of desired size into the dot pattern, and a selecting means 3 which selects which of the dot pattern stored in the storage means 1 and the dot pattern to be developed by the developing means 2 is used. The storage means where a vector font of size which is predicted to be high in use frequency like this is developed into the dot pattern previously and stored is provided, so the time of a output request for the dot pattern to the output can be shortened greatly.