An optical scanning device comprising: a light source configured to emit a plurality of laser beams; a scanning member configured to deflect and scan the laser beams emitted from the light source; a converging lens configured to converge the laser beams emitted from the light source, on a deflection surface of the scanning member; a first aperture provided between the converging lens and the scanning member and including a first opening portion configured to restrict a beam path width in a main scanning direction of the laser beams emitted from the light source; a second aperture provided between the light source and the converging lens and including a second opening portion and a cylindrical portion, the second opening portion being configured to restrict a beam path width in a sub scanning direction of the laser beams emitted from the light source and being formed in the cylindrical portion; a support member including a cylinder supporting portion that is formed in a shape of a hole extending between a front surface and a rear surface of the support member, and that pivotably supports the cylindrical portion of the second aperture; a first base portion to which the first aperture is fixed by adhesion fixing; and a second base portion to which the support member is fixed by adhesion fixing, wherein the first base portion includes a first pass-through portion that is formed to pass through between an upper surface and a lower surface of the first base portion, wherein the first pass-through portion includes a restriction portion that includes projections that respectively project from left and right end portions toward an inside of the first pass-through portion and are inserted in groove portions formed on the first aperture to extend in an up-down direction, a gap with a predetermined adjustment width is formed between the restriction portion and each of the left and right of the groove portions of the first aperture, the first aperture being inserted in the pass-through portion, the second base portion includes a second pass-through portion that is formed to pass through between an upper surface and a lower surface of the second base portion and in which the support member is inserted, and the second pass-through portion includes a restriction portion that includes projections that respectively project from left and right end portions toward an inside of the second pass-through portion, are inserted in groove portions formed on the support member to extend in an up-down direction, and are formed to extend between the upper surface and the lower surface of the second base portion. a light source configured to emit a plurality of laser beams; a scanning member configured to deflect and scan the laser beams emitted from the light source; a converging lens configured to converge the laser beams emitted from the light source, on a deflection surface of the scanning member; a first aperture provided between the converging lens and the scanning member and including a first opening portion configured to restrict a beam path width in a main scanning direction of the laser beams emitted from the light source; a second aperture provided between the light source and the converging lens and including a second opening portion and a cylindrical portion, the second opening portion being configured to restrict a beam path width in a sub scanning direction of the laser beams emitted from the light source and being formed in the cylindrical portion; a support member including a cylinder supporting portion that is formed in a shape of a hole extending between a front surface and a rear surface of the support member, and that pivotably supports the cylindrical portion of the second aperture; a first base portion to which the first aperture is fixed by adhesion fixing; and a second base portion to which the support member is fixed by adhesion fixing, wherein the first base portion includes a first pass-through portion that is formed to pass through between an upper surface and a lower surface of the first base portion, wherein the first pass-through portion includes a restriction portion that includes projections that respectively project from left and right end portions toward an inside of the first pass-through portion and are inserted in groove portions formed on the first aperture to extend in an up-down direction, a gap with a predetermined adjustment width is formed between the restriction portion and each of the left and right of the groove portions of the first aperture, the first aperture being inserted in the pass-through portion, the second base portion includes a second pass-through portion that is formed to pass through between an upper surface and a lower surface of the second base portion and in which the support member is inserted, and the second pass-through portion includes a restriction portion that includes projections that respectively project from left and right end portions toward an inside of the second pass-through portion, are inserted in groove portions formed on the support member to extend in an up-down direction, and are formed to extend between the upper surface and the lower surface of the second base portion.