A multilayer film reflector for X-rays has alternately stacked layers formed on a substrate and comprising a layer (high refractive index layer) comprising a material having a large difference between a refractive index to soft X-ray and a refractive index in vacuum, and a layer (low refractive index layer) comprising a material having a small difference between a refractive index to soft X-ray and a refractive index in vacuum, wherein at least one intermediate layer having a crystalline structure is provided between the low refractive index layer and the high refractive index layer. Thereby, the crystallization of the low refractive index layer is promoted, the refractive index of the low refractive index layer is lowered, so that the reflectance of the multilayer film reflector is improved.