According to one embodiment an anchor for a vertical formwork is provided that includes a fixed part suitable for being fixed to a formwork panel and fixing means for fixing the fixed part to the formwork panel. The fixing means includes a fixing key suitable for being housed in a hole of the formwork panel, the fixing key comprising an off-centered stop with respect to the axis of rotation of the fixing key, such that in a first angular position the off-centered stop of the fixing key can be introduced in the hole of the formwork panel and in a second angular position the off-centered stop is retained by the formwork panel, and therefore the anchor is fixed to the formwork panel.