A first press unit 2 presses each of a plurality of signatures S along a fold f, the signatures being supplied one at a time with the fold facing forward. The unit is arranged a signature conveyance unit 3 that conveys each signature received from the first press unit while controlling the attitude to make the fold orthogonal to the conveyance direction. The unit is arranged a gluing unit 4 that applies glue to both lateral edges of a top surface of each signature received from the signature conveyance unit. The unit is arranged an accumulation unit 5 that sequentially stacks the signatures received from the gluing unit on one another while jogging the stacked signatures to form a book block B. The unit is arranged a second press unit 6 that discharges the book block received from the accumulation unit after pressing the same along the folds.