To provide an optical scanning apparatus which is strong against an external stress while suppressing an increase in the number of parts, an inserting portion 6 into which a laser light source unit 1 can be inserted is provided for a frame member 5. In a state where the laser light source unit 1 has been inserted into the inserting portion 6, the laser light source unit 1 and the inserting portion 6 of the frame member 5 are interference-fitted in two positions (front edge side fitting portion 4a and front edge side contact portion 6a; root side fitting portion 4b and root side contact portion 6b) which are away from each other in an optical axial direction.