Provided is a multi charged particle beam writing apparatus including: an emission unit emitting a charged particle beam; a restriction aperture unit having a first opening having a variable opening area, the restriction aperture unit shielding a portion of the charged particle beam; a shaping aperture array substrate having a plurality of second openings, the shaping aperture array substrate forming multiple beams by allowing the shaping aperture array substrate to be irradiated with the charged particle beam passing through the first opening and allowing a portion of the charged particle beam to pass through the plurality of second openings; and a blanking aperture array substrate having a plurality of third openings, each beam of the multiple beams passing through the plurality of third openings, the blanking aperture array substrate being capable of independently deflecting each beam of the multiple beams.