An apparatus for manufacturing security paper, comprising at least one main forming roller, which is provided with a lower portion or forming portion, which is arranged inside a forming box that contains a paper paste, an upper portion or deposition portion, which is arranged below a collecting wire that can move along an advancement direction and is designed to receive, at a collecting face, the sheet formed on the forming roller, and a device for depositing security elements that is arranged upstream of the main forming roller along the advancement direction of the collecting wire and is adapted to deposit the security elements at the collecting face.