An infant seat for motorcars includes anchor being operable to engage a receiving element being provided in the motorcar. The infant seat has a framework fixedly attached to the lower face of the base of the seat and is fitted with the anchor, the anchor being actuated by a pneumatic device being fitted to the framework and actuated by a control being made up by an articulated lever, the control being accessible through the front edge of the base of the seat, the manual controls being operable for deactivating the anchor being found at the front edge.