PURPOSE: To enable printing in a small area and enable stable printing of a long character string, by fitting a detachable stabilizing frame to a main body of a handy printer to enhance the stability of movement.

CONSTITUTION: Fitting holes 11, 12 for printing which consist of circular holes are provided at positions corresponding to fitting dowels 7, 8 for printing. Further, a stand-fitting hole 13 consisting of a slot is provided correspondingly to a stand-fitting dowel 9. When a stabilizing frame 10 is fitted to a casing 1 from the side of a thermal head 2, guide parts 14, 14' of the frame 10, which are formed of a plastic resin and are springy, are opened to the left and right sides to ride over the dowels 7, 8, and the dowels 7, 8 are engaged with the holes 11, 12. As a result, the frame 10 is firmly fixed to the casing 1, and the casing 1 can be stably moved without being inclined to the forward, rearward, left or right sides.