To provide a multiplayer film reflector corrected in the surface shape of multiplayer films by controlling the layer number of multiplayer films without damaging the multiplayer films, a manufacturing method thereof, and a soft X-ray exposing device and soft X-ray optical system equipped with the multiplayer reflector.

In this manufacturing method of multiplayer film reflector, the multiplayer film reflector is formed by forming a multiplayer film 2 comprising at least two kinds of materials differed in refractive index alternately laminated in a prescribed periodic length on a substrate 1, and a multiplayer film 3 having a periodic length substantially equal to the multiplayer film 2 is laminated in a desired range on the multiplayer film 2, thereby, the phase of reflecting wave surface of the multiplayer film reflector is corrected.