To provide a method and device capable of economically manufacturing a small number of covers including one cover.

Covers 8 having different dimensions are manufactured by being positionally adjusted by a motor in accordance with an operation position specified for a cover 8 to be manufactured next on a case-by-case basis while a guide part of a paper supply part 20 for aligning at least cover paper 2 and spine paper 3 and a tucking device of a side tucking station 43 continues production, and while being temporally synchronized with passage of the respective covers 7, 8, and the cover paper 2, the spine paper 3 and a cover blank 4 corresponding thereto.