To satisfactorily reduce the quantity of data and to suppress the cost of a font data processor by deciding whether the font data read out of a font memory part are compressed or not and then defrosting the font data if compressed.

The compressed font data 5 and the non-compressed font data 6 are stored in a font memory part 1 and then read out when a character code 4 is inputted from an external device. Then a decision part 2 decides whether the data 5 or 6 is read out, and both data 5 and 6 are outputted on the different routes. The data 5 is defrosted at a defrosting part 3, and the data 6 is directly outputted as output 7. Thus, the quantity of data can be satisfactorily reduced and the cost of a font data processor can be suppressed.