A liquid crystal layer including a polymerizable monomer and a liquid crystal composition exhibiting a blue phase is provided between a first substrate and a second substrate which are bonded to each other with a sealant. Further, the sealant and part of the liquid crystal layer are covered by a light shield and a first light irradiation treatment is performed on the liquid crystal layer with use of the light shield as a mask, whereby a first region in which the polymerizable monomer is polymerized is formed. Furthermore, a second light irradiation treatment is performed on the liquid crystal layer after the light shield is removed, whereby a second region having a lower degree of polymerization of the polymerizable monomer than the first region is formed.