[en] The magnetic behaviour of the 58 K superconductor oxycarbonate thin film, which consists of an intergrowth of several members of a family with agreement composition (CaCuO₂)_m(Ba₂CuCO₃O₂)n has been studied. Its pinning properties in terms of critical current densities and irreversibility line have been established using their hysteresis cycles. Typical J_c was calculated to approximately 10⁵ A cm^-2 at 5 K in zero field. Finally, the irreversibility line is compared to those obtained by Kumakura et al. (1994) on bulk oxycarbonate superconductors synthesized at high pressure. (author)