A printer of a wire-dot impact type is provided forwardly of the housing an inlet opening for introducing a printing paper to the inside and has an outlet opening provided at a rear side of the housing for discharging the printing paper to the outside. The printing paper is transported by cooperation of a tractor arranged near the outlet opening and a feed roller arranged near the inlet opening, to thereby run inside the housing in substantially a straight path of travel from the inlet opening to the outlet opening, during which the printing paper is printed by means of a platen and a printing head, both provided between the feed roller and the tractor. A pair of guide members are provided between the feed roller and the printing unit and between the printing unit and the tractor, respectively, to thereby feed the printing paper along the straight path of travel.