A windscreen wiper device of the flat blade type, particularly for automobiles, comprising an elastic, elongated carrier element, as well as an elongated wiper blade of a flexible material, which can be placed in abutment with a windscreen to be wiped, which wiper blade includes at least one longitudinal groove, in which groove a longitudinal strip of the carrier element is disposed, which wiper blade comprises a connecting device for an oscillating arm, wherein the oscillating arm near one end thereof is pivotally connected to the wiper blade and near the other end thereof is connected to a mounting head on a drive shaft for transferring a reciprocal movement to the wiper blade, with the special feature that the connecting device comprises at least two opposing spaced-apart sidewalls each comprising a protrusion extending sidewardly and outwardly, wherein the connecting device and the oscillating arm are interconnected by the protrusions pivotally and snappingly engaging into correspondingly shaped recesses of the oscillating arm, wherein the oscillating arm comprises a downwardly extending guiding tongue engaging into a guiding groove of the connecting device defined between the sidewalls thereof, and wherein the connecting device has an asymmetric form with respect to its middle transverse plane, seen in vertical direction, in order to ensure that the wiper blade can only be mounted on the oscillating arm in a predetermined orientation of the wiper blade relative to the oscillating arm.