A multiple charged particle beam writing method according to one aspect of the present invention includes performing writing, during writing in the k-th (k being an integer of at least one) stripe region, in the k-th extended region, which is obtained by extending the irradiation region in the first direction by a predetermined extension width, while deflecting multiple charged particle beams and moving the multiple charged particle beams in the second direction, and performing writing, during writing in the (k+1)th stripe region, in the (k+1)th extended region, which is obtained by extending the irradiation region in the first direction by the extension width, while deflecting the multiple charged particle beams and moving the multiple charged particle beams in the second direction.