To provide a multilayer film reflection mirror which hardly causes the deterioration of reflectance due to oxidation, and to provide an exposure device provided with the multilayer film reflection mirror.

The multilayer film reflection mirror is provided with: an Mo/Si multilayer film 6 having a structure in which a layer principally comprising Mo and a layer principally comprising Si are alternately and periodically formed on the surface of a substrate 4; and an Ru/Si multilayer film 8 having a structure in which a layer principally comprising Ru and a layer principally comprising Si are alternately and periodically formed on the Mo/Si multilayer film.