A folding device for a flat blank has a plurality of bearing blocks arranged in a row in a first direction, the mutual distance of which can be changed by a drive device and each of which has a support surface for the blank by a holding device. A plurality of folding blades are arranged at a distance next to one another in the first direction, at least one of the folding blades being arranged between immediately adjacent bearing blocks. The folding blades can be adjusted by changing a mutual distance with an additional movement component perpendicular to the blank. Adjacent bearing blocks are coupled in terms of movement via a linkage. The folding blade arranged between adjacent bearing blocks is connected to the linkage so a change in distance between the bearing blocks can be transferred by the linkage to the folding blade for the adjustment thereof.