A machine for tying pork meat in casings by means of twines, comprising: a fixed tube (8) for conveying the pork meat, which is open onto a cradle (2) for inserting the pork meat and leads proximate to a supporting roller bed (27); means adapted to follow the pork meat at the outlet of the fixed tube; at least one device (18) adapted to perform a translational motion at the peripheral region of the fixed tube, which comprises a flange (20) with twine passage holes provided with means which allow variations of the twine passage conditions; a pusher (6) adapted to determine the translational motion of the pork meat between the positions for resting within the cradle (2) and in the roller bed (27); a clipping unit (26) between the end of the fixed tube and the roller bed; jaws (28, 29) adapted to come into contact, with differentiated pressures, with the pork meat resting on the roller bed (27).