PURPOSE: To markedly reduce the re-registering operation load of register data accompanied by memory rearrangement processing as compared with conventional one.

CONSTITUTION: A control part 21 analyzes the printing data inputted from a host computer 1 to judge whether the rearrangement processing to a memory part 22 is necessary and, when it is judged that rearrangement is necessary, a memory control part 212 and a permanent memory control part 213 refer to discrimination data to register the printing data and discrimination data registered in the memory part 22 in the permanent memory part 23. After rearrangement processing to the memory part 22 is completed, the memory control part 212 and the permanent memory control part 213 read the printing data stored in the permanent memory part 23 while refer to the discrimination data registered in the permanent memory part 23 to re-register the same in the memory part 22.