A photostimulation apparatus includes an objective lens arranged to face a biological object, a light source configured to output light to be radiated toward the biological object via the objective lens, a shape acquisition unit configured to acquire information about a shape with a refractive index difference in the biological object, a hologram generation unit configured to generate aberration correction hologram data for correcting aberrations due to the shape with the refractive index difference on the basis of the information acquired by the shape acquisition unit, and a spatial light modulator on which a hologram based on the aberration correction hologram data is presented and which modulates the light output from the light source.