A method for driving a spatial light modulator includes setting a plurality of mirror elements in a first region into a state of phase 0, setting a plurality of optical elements in a second region adjacent in a Y-direction to the first region into a state of phase π, and setting auxiliary pattern elements consisting of a plurality of mirror elements arranged at a pitch P over a resolution limit of a projection optical system in an X-direction in a boundary region extending in the X-direction between the first region and the second region, into the state of phase π. In projecting a pattern onto an object with use of the spatial light modulator having the array of optical elements, the pattern can be formed in position accuracy or shape accuracy finer than the width of images of the optical elements.