An optical scanning device includes a cylindrical aperture, a support member, and a base portion. In the aperture, an opening portion restricts a beam path width of a laser beam emitted from a light source. The support member includes a cylinder supporting portion that pivotably supports the aperture. To the base portion, the support member is fixed by adhesion fixing. The base portion includes a pass-through portion that passes through between front and rear surfaces of the base portion and allows the support member to move in direction perpendicular to a pivoting axis of the aperture. The support member has a length such that its lower end portion projects from a rear surface of the base portion in the state where the support member has been inserted in the pass-through portion to such a position where laser beam is incident in the opening portion of the aperture.