A multi charged particle beam writing apparatus includes a stage to mount a target object thereon and to be movable, an emission unit to emit a charged particle beam, an aperture member, in which a plurality of openings are formed, to produce multiple beams by letting a region including the whole of a plurality of openings be irradiated with the charged particle beam and letting portions of the charged particle beam respectively pass through a corresponding opening of a plurality of openings, a reduction optical system to reduce the multiple beams, and a doublet lens, arranged at the subsequent stage of the reduction optical system, in which a magnification is 1 and directions of magnetic fluxes are opposite.