3D polymerization of C60 realizes under conditions of large plastic deformation at pressure 6–7 GPa and room temperature in the presence of CS2. The phase of 3D-polymerized C60 is identical to ultrahard fullerite synthesized from pure C60 at 18 GPa pressure: in both cases, the samples plough diamond during the rotation of the sample in a shear diamond anvil cell, bulk module is 585 GPa, and a sequence of phase transitions preceding to ultrahard phase is also the same in both cases (in the presence of CS2, the phase transitions take place at lower pressures than in pure C60). Raman and transmission microscope studies confirm the structure equivalence of samples of both types. The absence of sulfur in the structure of ultrahard fullerite synthesized in the presence of CS2 proves the catalysis role of CS2 in the 3D polymerization of C60.