Abstract: A security storage box for papers, such as banknotes or cheques, comprising an open-topped container and lid separate from the container and being formed to close the open top of the container. The container comprises substantially continuous peripheral container flange. This horizontal container flange is being provided with a plurality of through apertures. The lid includes a horizontal, substantially continuous peripheral lid flange formed to overly the container flange and is provided with lid hooks, formed and aligned to engage with the container flange apertures. To improve the resistance of the boxes against fraud and pilferage, the container flange around its peripheral outer edges of the side and end walls is integrally connected to a security flange extending parallel to the side and end walls in the direction of the bottom wall, the lid being provided with a cover flange being formed to overly the security flange at the side and rear end walls.