A cutting device for a lawnmower comprising: - a rotating element having a plurality of pairs of first and second slots, each of said first and second slots having an insertion hole , a curved sliding portion and an end proximal to the outer perimeter (Q) of said rotating element , - a plurality of blades each having a first and a second engagement end respectively with said first and second slots, each of said first and second engagement ends of said blades being designed to be inserted into said insertion holes and to slide alternately on one of said first and second slots respectively, each of said blades being designed to pass from: - an extracted position (P1) in which said first and second engagement ends of one determined blade are arranged to be abutted by said proximal ends of said first and second slots and said determined blade emerges at least partially from said outer perimeter (Q) of said rotating element , to - a retracted position (P2) wherein one between said first and said second engagement ends of said determinate blade is positioned at an intermediate position between said insertion hole and said respective proximal end and the other between said first and said second engagement ends is positioned in contact with said respective proximal end defining a rotation pivot of said determinate blade , said determinate blade not emerging with respect to said outer perimeter (Q) of said rotating element . - a rotating element having a plurality of pairs of first and second slots, each of said first and second slots having an insertion hole , a curved sliding portion and an end proximal to the outer perimeter (Q) of said rotating element , - a plurality of blades each having a first and a second engagement end respectively with said first and second slots, each of said first and second engagement ends of said blades being designed to be inserted into said insertion holes and to slide alternately on one of said first and second slots respectively, each of said blades being designed to pass from: - an extracted position (P1) in which said first and second engagement ends of one determined blade are arranged to be abutted by said proximal ends of said first and second slots and said determined blade emerges at least partially from said outer perimeter (Q) of said rotating element , to - a retracted position (P2) wherein one between said first and said second engagement ends of said determinate blade is positioned at an intermediate position between said insertion hole and said respective proximal end and the other between said first and said second engagement ends is positioned in contact with said respective proximal end defining a rotation pivot of said determinate blade , said determinate blade not emerging with respect to said outer perimeter (Q) of said rotating element . - an extracted position (P1) in which said first and second engagement ends of one determined blade are arranged to be abutted by said proximal ends of said first and second slots and said determined blade emerges at least partially from said outer perimeter (Q) of said rotating element , to - a retracted position (P2) wherein one between said first and said second engagement ends of said determinate blade is positioned at an intermediate position between said insertion hole and said respective proximal end and the other between said first and said second engagement ends is positioned in contact with said respective proximal end defining a rotation pivot of said determinate blade , said determinate blade not emerging with respect to said outer perimeter (Q) of said rotating element . <EOS>