A method of and an apparatus for producing a high strength double-ply corrugated paperboard including multiple-ply corrugated mediums (11a, 21a) laminated together between liners (12a, 22a) such that they are completely in contact with each other or partially in contact with each other at intervals to form a space therebetween for every corrugation, thereby capable of exhibiting a high compressive strength while having a small thickness to minimize the packaging size, and effectively absorbing outside shock applied to the package to keep the packaged goods more safe. The method includes the steps of forming a single-faced downward-corrugated paperboard (13) and a single-face upward-corrugated paperboard (23), preheating the paperboards, sensing positions of corrugations of the preheated paperboards, coating an adhesive on the corrugated mediums of the position-determined paperboards, guiding the adhesive-applied paperboards to a heating plate; and pressing the paperboards against each other at a desired pressure during the paperboards pass over the heating plate.