1. A structured illumination microscope device comprising: a diffraction grating; a projection optical system that projects light from a light source onto an object to be observed via the diffraction grating or bypassing the diffraction grating; a control unit that controls a direction and a phase of a pattern of the diffraction grating; an image-forming optical system that forms an image of the object to be observed on which the pattern of the diffraction grating is projected; an image sensor that generates an image by capturing the image formed by the image-forming optical system; and computing unit that generates a super-resolution image of the object to be observed on the basis of at least one unmodulated image generated by the image sensor and an image generated by the image sensor on the basis of patterns in at least three directions of the diffraction grating; and the control unit being configured to perform control such that a pattern in at least one direction of the diffraction grating is radiated uniformly on the object to be observed when a plurality of the super-resolution images is generated.