PURPOSE: To improve the efficiency of both print processing and application of a memory by using a storing region for print data of the memory as a circulating memory.

CONSTITUTION: When a display is given to show that the value of a print data number counting register 4 is set at ≥1 with printing, the print data is extracted out of an address indicated by a print data extracting address pointer 3. Then the printing is started. The address next to the address where the final data is extracted is set to the pointer 3. When the final address of a print data region 1 is obtained under extraction of the print data, the tip address of the region 1 is reset to continue extraction of data. When the extraction is through with data, the data number extracted out of the value of the register 4 is subtracted. With continuation of such operations, the region 1 can be used as a circulating memory.