There is provided a single facer consisting of an upper roll, a lower roll, a pasting device and a pressure member in parallel with the lower roll for manufacturing single-faced corrugated board. The single facer is characterized by the provision of a suction conveyor having belts for conveying single-faced corrugated board, the suction conveyor being disposed at the side of another sheet in the transport passage of the single-faced corrugated board in the proximity of the engaging point between the lower roll and pressure member, thereby preventing the strip-off or separation of a contact portion between the corrugated sheet and another sheet by means of the structure, which is extremely simple and compact in form.