Band structures and transmittance of a one-dimensional confined antiferromagnetic photonic crystal were calculated by the transfer matrix method. Besides photonic band gaps, the results demonstrate the existence of another type of frequency gaps which principally depends on the antiferromagnetic resonant character and the confined dimension. In the vicinity of the antiferromagnetic resonant frequency, a relatively wider frequency gap can be obtained by properly changing the antiferromagnetic anisotropic-axis orientation and the confined dimension. It is about 15 times wider than that of bulk antiferromagnetic material. On certain conditions, the confined photonic crystal can be transparent in the frequency gap of corresponding bulk antiferromagnetic material for some discrete modes. The typical transmission spectra are presented and agree with the calculated band structures.