An apparatus for manufacturing security paper, comprising at least one main forming roller (2), which is provided with a lower portion or forming portion (3), which is arranged inside a forming box (4) that contains the paper paste, an upper portion or deposition portion (5), which is arranged below a collecting wire (6) that can move along an advancement direction and is designed to receive, at a collecting face (6a) the sheet (7) formed on the forming roller (2), and a device (8) for depositing security elements (201) that is arranged upstream of the main forming roller (2) along the advancement direction (100) of the collecting wire (6) and is adapted to deposit the security elements (201) at the collecting face (6a).