In a printing device in which a printing material is printed on or applied to a to-be-printed surface of a circuit board through a screen mask for printing having openings formed therein in a predetermined pattern, it is intended to reliably remove cream solder remaining in the openings in the screen mask. After an air suction mechanism (19) has its flow rate controlled by a flow rate controller (20). An air suction section (15) is lifted until its front end contacts with the screen mask (5), the air suction mechanism (19) starts cleaning by sucking air from the openings (6) in the screen mask (5). An inspecting camera (2) is used to observe the cream solder (4) remaining in the openings (6) after cleaning, and the air suction flow rate is controlled according to the results thereof to effect cleaning again.