Projection exposure device and production exposure method

A projection exposure device (10) that comprises a mask mark illumination light source (21) that can radiate exposure light or first alignment light (L1) that has the same wavelength as the exposure light at a mask mark (MM), a work mark illumination light source (31) that can radiate second alignment light (L2) that has a different wavelength from the exposure light at a work mark (WM), an imaging device (32), and an imaging optical system (40). The imaging optical system (40) comprises: a first dichroic prism (41) that synthesizes the first alignment light (L1) and light from the work mark (WM) and emits the synthesized light toward the imaging device (32); and an optical path length modification optical system (42) that makes the first alignment light (L1) branch and converge. Relative to the imaging device (32), the optical positions of the work mark (WM) and an image (MMI) of the mask mark (MM) are equivalent. The present invention thereby provides a projection exposure device and a projection exposure m