PURPOSE: To find out a specific control code easily by constituting a non-symbol font pattern corresponding to a predetermined non-symbol code so as to be different from a non-symbol font pattern corresponding to other non-symbol code than the predetermined code.

CONSTITUTION: When a code is an escape code, a data develop means 3 reads out a pattern data corresponding to the escape code from a pattern data memory means 2 so as to develop the pattern data. A develop data memory means 4 stores the developed pattern data. When the code is not a symbol code nor the escape code, the data develop means 3 reads out a pattern data of a period '.' from the pattern data memory means 2 so as to develop the pattern data. The develop data memory means 4 stores the developed pattern data. A print control means 6 receives the developed data from the develop data memory means 4 so as to control printing operation for 1 line.