Mounting auxiliary member and optical scanning device including the same

An optical scanning device, which is configured to irradiate a laser beam on the basis of image data, comprising:

• a mounting auxiliary member interposed between a light source holding member holding a light source and a head part of a screw when a leading end part of the screw penetrating through the light source holding member is screwed to a screw hole perforated in a support member in order to support the light source holding member to the support member,
• wherein the mounting auxiliary member includes:
• a rotary member having a first through hole through which a shaft part of the screw penetrates and configured so as to co-rotate with the screw as the head part of the screw comes into contact with a peripheral edge part of the first through hole;
• and
• a stationary member interposed between the rotary member and light source holding member, having a second through hole into which the shaft part of the screw penetrating through the first through hole is movably inserted, and configured to hold the rotary member while permitting the rotary member to slidably rotate.