PURPOSE: To perform a screen shadowing which can sufficiently emphasize, a character even if the density of the screen shadowing is low.

CONSTITUTION: When a character modification key is operated, a modification data based on a net pattern 50 with a frame is registered in an input buffer of RAM 33. Thereafter, when a print performing key is operated, the pattern data of a net pattern 51 is developed on a printing buffer R2 of the RAM 33. Then, the pattern data of a frame pattern 52 is developed on a printing buffer R. When this development is finished, a character and a net pattern with a frame are printed in layers on a tape by means of a thermal head 41.