A pressing mechanism that presses a dam member 30 against a screen mask 12 has a guide shaft 32 that guides a direction of movement of the dam member 30 during pressing operation and a compression spring 33 that forces the dam member 30 in an axial direction of the guide shaft 32. A printing pressure value at which the dam member 30 is pressed against the screen mask 12 is made stable, to thus make stable an effect of preventing effluence of the paste to the outside of a print width on the screen mask 12.