PURPOSE: To form dot matrix data by comprising a display apparatus capable of conducting a matrix-form display, and an input device controlling the display and erasure of matrix.

CONSTITUTION: An operation part 1 is provided with a display apparatus 2, an input device 3, and an address display part 4. The title printer comprises a memory device 6 registering inputted dot matrix data to a specified address, a printing mechanism part 7 recording said data, and a control part 5 controlling the display and erasure to the display apparatus 2, the registration to the memory device 6, and the recording to the printing mechanism part 7. The display apparatus 2 is composed of a matrix of 9×9, a cursor is displayed on the intersection in the matrix and moved to an arbitrary position by a cursor key 3a, and a black dot is displayed corresponding to the cursor by pressing a display key 3b. After an arbitrary character or graphic is displayed on the display apparatus 2, an address on which it is to be registered is inputted by a numeric key 3e and stored in the memory device 6 by pressing a register key 3d. In this manner, the forming and registration of dot matrix data such as a pi- character registration can be conducted.