An electron beam exposure method includes the steps of: preparing an exposure mask having a plurality of opening patterns formed by dividing a drawing object pattern into exposable regions; and drawing the drawing object pattern by performing exposure with an electron beam passing through the opening patterns of the exposure mask. Each end portion serving as a joint in each opening pattern of the exposure mask is provided with a joining portion tapered in a width of the opening pattern. The exposure is performed in such a way that portions drawn through adjacent joining portions overlap each other.