PURPOSE: To provide a belt pressing type single facer capable increasing pressing force necessary for bonding core paper and a liner without increasing the tension of an endless belt.

CONSTITUTION: In a single-faced corrugated cardboard producing machine having an endless belt 4 arranged on the downstream side of upper and lower corrugation rolls 1, 2 delivering core paper 5 in a corrugated shape so as to be in contact with the upper corrugation roll 1, the core paper 5 delivered in a corrugated state and the liner 6 allowed to meet with the core paper 5 through a separate route are held between the endless belt 4 and the corrugation rolls 1, 2 to be fed and bonded through the paste provided to the corrugation top parts of the core paper and at least one pressure roll 8 capable of adjusting the pressing force to the corrugation rolls through the core paper 5, the liner 6 and the endless belt 4 is provided.