An optical writing device performs writing by scanning an image surface of a photoconductor with light, and includes a light source unit including a light source that emits light, a deflection unit that deflects and scans the light, an optical element unit for the light, and a housing unit that holds the light source unit, the deflection unit, and the optical element unit. The housing unit includes a vibration isolator that isolates vibration transmitted from a vibration antinode where distribution of vibration in a sub direction perpendicular to a scanning direction of the light on the image surface of the photoconductor is maximum to at least one of seat face parts for the light source unit and the optical element unit having optical sensitivity in the sub direction, in a bottom face part of the housing unit, and a rigidity enhancer that increases rigidity of the seat face part.