A printing apparatus having shorter length in the longitudinal direction and a dust-protecting feature is disclosed. The printer includes a main frame, a subframe assembly, first and second pulse motors each have a reduction gear drive mechanism, a thermal head, a platen roller, a rotary blade, and a stationary blade. The first motor for driving the platen roller and the second motor for driving the rotary blade are disposed between two side plates provided one on each end of the main frame. The reduction gear drive mechanisms are substantially sealed and disposed inside the corresponding side plates. Two pulleys and a timing belt are provided outside each of the side plates.