An exposure method for exposing a workpiece on the basis of near-field light escaping from an opening of a mask. The method includes projecting non-polarized exposure light having a predetermined wavelength, emitted from a laser light source and passed through a depolarization device and a diffusion device, onto an exposure mask having a light blocking film formed with a plurality of rectangular openings therein, the openings having (i) a width in a widthwise direction not greater than one-third of the wavelength of the exposure light and (ii) two or more lengthwise directions extending along the mask surface, so that near-field light escaping from the openings performs exposure of a pattern on the basis of the openings.