An exposure method that transfers a pattern formed on a mask onto an object to be exposed via a projection optical system that is at least partly immersed in liquid. The exposure method forms on a pupil of the projection optical system an effective light source that emits, from an axis orthogonal to an optical axis of the projection optical system, light that has an incident angle θ upon the object, wherein the light includes only s-polarized light in an area of an incident angle θ that satisfies 90°−θNA≦θ≦θNA, where θNA is the largest value of the incident angle θ.