A printer apparatus is disclosed. The printer includes: a thermal head having heat generating elements arranged in the form of a line extending longer than the width of a printing medium in the width direction of the printing medium substantially orthogonal to the conveying direction thereof; and a platen disposed opposite to the thermal head with a conveying path for the printing medium interposed between them so as to cooperate with the platen to sandwich the printing medium beyond the width of the printing medium with an ink ribbon interposed. The platen is put in contact with an end portion of the thermal head located beyond the width of the printing medium.