This adjusting method can determine the precise deflection amount of mask deflectors corresponding to each aperture pattern by precisely measuring the position of the beam deflected by the mask deflectors in relation to that of each aperture pattern in an electron beam exposure apparatus, comprising an electron gun, a block mask, plural mask deflectors that deflect the electron beam so as to pass through one of the plural aperture patterns selectively, convergent devices that converge the electron beam onto a specimen, and deflectors that deflect the electron beam on the specimen. The electron beam exposure apparatus has the ability to expose the patterns corresponding to the selected aperture patterns, at one time, and in which the plural aperture patterns are square or rectangular and arranged in a matrix form, each aperture pattern has a square or rectangular maximum aperture area that limits the area in which each aperture is formed, the block mask has at least one adjusting aperture pattern equipped with independent apertures of the same shape arranged along the opposite sides of the maximum aperture area, and the mask deflectors are adjusted so that the intensity of the beam, which is radiated onto the specimen, at the portion of the independent apertures of the same shape arranged along the opposite sides of the adjusting aperture pattern, is uniform and maximum.