The invention relates to a tenderizing machine for tenderizing pieces of meat, the machine comprising a first tenderizing roller (1) rotating about a first axis (3) supported in a fixed position in a structure (51), a second tenderizing roller (2) rotating about a second axis (4) parallel to said first axis (3) and movably supported in said structure (51) with the possibility of being separated from the first axis (3) against the force of antagonist means due to the effect of the passage of the pieces of meat between said first and second tenderizing rollers (1, 2), and drive means for rotating the first and second tenderizing rollers (1, 2) in opposite directions comprising a first motor (5) operatively connected by means of a first mechanical transmission (7) to rotate the first tenderizing roller (1), and a second motor (6) operatively connected by means of a second mechanical transmission (8) to rotate the second tenderizing roller (2).