Provided is an optical scanner for observing an image that is formed by performing two-dimensional scanning with the aid of a swinging movable mirror, using light beams modulated on the basis of image information and emitted from a light source unit. An optical scanner of the present invention includes a scanning device and a fixing member having an attachment portion for attachment of the scanning device, the scanning device including a movable mirror, an elastic support portion supporting the movable mirror such that the movable mirror can swing around a swinging center, a support base supporting the elastic support portion, and a swinging unit for swinging the movable mirror. A first surface of the attachment portion is formed on a plane of a surface of the movable mirror. A second surface of the attachment portion is formed on a plane which is perpendicular to the surface of the movable mirror and includes the swinging center. A third surface of the attachment portion is formed on a plane which is perpendicular to a surface of the movable mirror and includes a center line perpendicular to the swinging center in the surface of the movable mirror.