A line thermal printer includes a platen roller and a line thermal head including a plurality of heating elements. The heating elements are disposed to face the entire area of a recording sheet in a width direction of the recording sheet and selectively generate heat. The recording sheet is interposed between the platen roller and the line thermal head. The line thermal printer performs printing at the interposed position on the recording sheet by the selective generation of heat of the heating elements while the recording sheet is moved. The line thermal printer includes a foreign material blocking member. The foreign material blocking member is disposed upstream of the interposed position to come in contact with an upper surface of the recording sheet, and prevents foreign materials, which are placed on the upper surface of the recording sheet, from being moved toward the interposed position.