A photopolymerization initiator including (a) a photosensitizer, (b) a tertiary amine compound and (c) an aryliodonium salt wherein, as the aryliodonium salt (c), there is selected the one that generates an acid having a dissociation constant of not less than -3.0 in water of 25°C.
                            一种光聚合
引发剂,包括(a)一种光敏剂,(b)一种叔胺化合物和(c)一种芳基
碘鎓盐,其中,作为芳基
碘鎓盐(c),选择在 25°C 
水中生成解离常数不小于-3.0 的酸的一种。