PURPOSE: To continuously produce single-faced corrugated cardboard even when the replacement of a belt becomes necessary because of abrasion or cutting in a single facer pressing a liner to core paper, which is corrugated by the endless belt partially brought into contact with the outer periphery of a corrugation roller under pressure and subsequently coated with paste, to form the single-faced corrugated cardboard,

CONSTITUTION: A part of a liner laminating endless belt 4 is brought into contact with the outer periphery of a lower stage roll 2 feeding core paper (a) corrugated and coated with paste in the peripheral direction thereof and at least one of first and second guide rollers 5, 6 bringing a part of the endless belt 4 into contact with the lower stage roll 2 is provided so as to be brought into contact with the lower stage roll 2 in a freely separable manner. When the replacement of the belt 4 becomes necessary because of abrasion or cutting, the belt 4 is detached, the guide rollers free in contact and separation are brought into contact with the lower stage roll 2 and a liner (b) is pushed against the core paper (a) by the guide rollers to continuously produce a single-faced corrugated cardboard A.