A deformable mirror has a first deforming portion that has a reflection surface, a second deforming portion surrounding the first deforming portion and has lower mechanical stiffness than that of the first deforming portion, a fixing portion fixing a peripheral portion of the second deforming portion, deformer for acting on the first deforming portion to deform the first deforming portion and second deforming portion, and restrictor for restricting deformation in a main deforming direction of a portion of the first deforming portion that is outside an operation region of the deformer.