Slit-patterned Mn-Ir/Fe-Si exchange-coupled film was annealed under an applied dc magnetic field in vacuum, and its magnetic properties were then evaluated. When a film without slits was annealed, the saturation field Hs in the hard axis direction decreased with increasing annealing temperature, and the ferromagnetic resonance frequency after annealing was lower than that before. On the other hand, when the slit-patterned film was annealed, the saturation field Hs after annealing was larger than that of the film without slits, due to the effect of a shape anisotropy field. In addition, the ferromagnetic resonance frequency changed very little with the annealing temperature. Hence, on account of the shape anisotropy resulting from the introduction of slits, Mn-Ir/Fe-Si exchange-coupled film has a higher FMR frequency. It will be applicable in device fabrication that includes thermal processes because of its uniaxial anisotropy, which includes shape anisotropy that is not influenced by thermal processes.