A lens array unit includes a lens array including a plurality of lenses, a first side plate, and a second side plate, the first side plate and the second side plate being configured to hold the plurality of lenses therebetween, and a frame made of resin and including a first supporting portion and a second supporting portion, the first supporting portion being in contact with an outside surface of the first side plate, the second supporting portion being in contact with an outside surface of the second side plate, the first supporting portion and the second supporting portion being configured to hold the lens array therebetween and support the lens array. The outside surface of the first side plate includes a plurality of first concave portions spaced from each other in an array direction of the lenses and configured to fit with the first supporting portion.

A lens array unit includes a lens array including a plurality of lenses, a first side plate, and a second side plate, the first side plate and the second side plate being configured to hold the plurality of lenses therebetween, and a frame made of resin and including a first supporting portion and a second supporting portion, the first supporting portion being in contact with an outside surface of the first side plate, the second supporting portion being in contact with an outside surface of the second side plate, the first supporting portion and the second supporting portion being configured to hold the lens array therebetween and support the lens array. The outside surface of the first side plate includes a plurality of first concave portions spaced from each other in an array direction of the lenses and configured to fit with the first supporting portion.

An optical scanning apparatus includes first and second light source units including respective light sources; a rotating polygon mirror that performs deflection scanning of laser beams emitted from the light sources included in the first and second light source units; and a positioning member including a first abutting portion on which the first light source unit abuts and a second abutting portion on which the second light source unit abuts, the positioning member positioning the first and second light source units. The first and second light source units are positioned by the positioning member and arranged next to each other in a rotation axis direction of the rotating polygon mirror. The positioning member is a single member disposed between the first and second light source units in the rotation axis direction.

An optical scanning apparatus includes first and second light source units including respective light sources; a rotating polygon mirror that performs deflection scanning of laser beams emitted from the light sources included in the first and second light source units; and a positioning member including a first abutting portion on which the first light source unit abuts and a second abutting portion on which the second light source unit abuts, the positioning member positioning the first and second light source units. The first and second light source units are positioned by the positioning member and arranged next to each other in a rotation axis direction of the rotating polygon mirror. The positioning member is a single member disposed between the first and second light source units in the rotation axis direction.