Diamond-like carbon films have been irradiated with x-rays from a synchrotron radiation source. Raman measurements showed that the fraction of tetrahedrally coordinated (sp(3)) bond in the film increased with the increase of x-ray irradiation time, whereas it decreased as the annealing temperature increased. It was confirmed by electron spin resonance measurements that the number of spins did not change by x-ray irradiation. These results indicated that the transition from sp(2) to sp(3) bond takes place by nonthermal Coulomb repulsive rearrangement of atoms after inner-shell electron excitation.