A method of producing a retardation optical element, comprising the steps of:
- applying a first liquid crystal comprising at least one type of polymerizable monomer or oligomer molecules having cholesteric regularity to an alignment layer that has been so formed that a surface thereof exerts alignment regulation power in substantially one direction, thereby aligning the first liquid crystal by the alignment regulation power of the surface of the alignment layer;
- and
- three-dimensionally crosslinking and solidifying the aligned first liquid crystal, thereby forming a first retardation layer that selectively reflects light whose wavelength falls in a range different from a wave range of incident light.