In one embodiment, a charged particle beam writing apparatus includes a positioning deflector adjusting an irradiation position of a charged particle beam radiated to a substrate which is a writing target, a fixed deflector which is disposed downstream of the positioning deflector in a traveling direction of the charged particle beam, and in which an amount of deflection is fixed, a focus correction lens performing focus correction on the charged particle beam according to a surface height of the substrate, and an object lens focusing the charged particle beam.