To provide a lighting optical device capable of dimming illuminance of the light output from a light source, across such wide range as up to the illuminance requested for various measurements on a substrate side, while suppressing change of the volume of light incident on an observation optical system, and to provide an exposure apparatus and device manufacturing method.

Exposure apparatus 11 includes a lighting optical device 13 which guides exposure light EL output from a light source 12 to a reticle R. The lighting optical device 13 includes an optical attenuator 20 capable of dimming the exposure light EL output from the light source 12 across such narrow dimming range as 0-90% of dimming rate, a dimming unit 26 capable of dimming the exposure light EL across such wide dimming range as 0-99% of dimming rate, an observation optical system 25 for observing optical characteristics of the exposure light EL in the middle of the optical path between the dimming unit 26 and the optical attenuator 20.