In the application of cholesteric liquid crystal (CLC) polymer film to mono-color polarizers, diffusive reflection is preferred rather than mirror reflection at the point of visibility. This led us to develop a diffusion-type CLC (D-CLC) film. The newly developed D-CLC film exhibits high circular dichroism with bright color reflection that can be observed from almost all directions. The layer structure of the D-CLC film was directly confirmed by analysis with transmission electron microscopy (TEM). It was found that the diffusive property and polarization of the reflected light are mainly affected by the layer structure of the D-CLC.