Disclosed is a folder-gluer comprises: a conveyance device configured to convey a corrugated paperboard sheet; a pair of bending bars configured to bend a first panel and a fourth panel of the corrugated paperboard sheet from 0 degree to about 90 degrees; a pair of bending plates provided in a zone where the first and fourth panels are bent from 0 degree to about 90 degrees, and configured such that distal ends thereof come into contact, respectively, with crease lines of the first and fourth panels or vicinities of the crease lines, wherein each of the bending plates is configured to be pushed and moved outwardly in a width direction, by a push-out device; a detector configured to detect a position of the corrugated paperboard sheet; and a control device configured to control the push-out device.