An optical scanner for scanning light signals, such as light beams, including an electrostrictive element attached at one end thereof to a base body, a convex mirror fixed to the other end of the electrostrictive element, a driving circuit for changing a voltage applied to the electrostrictive element, and an emitter for emitting a light beam to the surface of the convex mirror in a direction different from the modified direction of the electrostrictive element. When the applied voltage to the electrostrictive element changes by the driving circuit during reflecting light beams on the convex mirror surface, the electrostrictive element is modified according to the applied voltage. Simultaneously light beams are scanned over a wide range, even if the modified volume is small, due to continuous change of deflection angles of beams according to the radius of the curvature of the convex mirror.