A multi charged particle beam writing apparatus includes a dose calculation unit to calculate a first dose resolving the resist of the target object, for a first beam of the multiple beams, corresponding to a pattern forming region, in which a pattern is arranged; and to calculate a second dose not resolving the resist, for a second beam of the multiple beams, corresponding to a no-pattern forming region, which surrounds the whole perimeter of the pattern and in which no pattern is arranged, and a deflection control unit to control a plural blankers so that a dose of the first beam is to be the first dose calculated and a dose of the second beam is to be the second dose calculated.