A laser scanning optical device includes: alight source having a plurality of emission points; a plate-like light source holder which holds the light source in a center of the light source holder; a base arranged to face the light source holder; and an attitude adjusting part which adjusts an attitude of the light source by adjusting a tilt of the light source holder, and the attitude adjusting part includes an inclined part and an inclination conveying part, and adjusts the tilt of the light source holder with respect to the base by displacing an abutting position of the inclined part corresponding to the inclination conveying part along an inclined surface of the inclined part.