Abstract: A working machine comprising a working head (1) having a spindle (10) and which is movable in a xyz working space and further comprising a clamping device (2,3) for clamping pieces (100) to be worked by said machine. The clamping device (2,3) comprises first (21, 31) and second (22,32) clamping means which are movable along a z direction between a first operative position, in which they are in clamping contact with pieces (100) to be worked, and a second non-operative position, in which they are at a distance from said pieces (100), said first (21, 31) and second (22, 32) clamping means being fixed with respect to an xy working plane when in said first operative position and being movable together with said working head (1) in said xy working plane when in said second non-operative position, said first (21, 31) and second (22, 32) clamping means being alternatively moved between said first and second position during a working cycle of said working machine.