A drive transmitting device having a partly untoothed gear partly having an untoothed portion, and a driven gear capable of meshing which the partly untoothed gear, and transmitting rotation from the partly untoothed gear to the driven gear is characterized in that in the partly untoothed gear, of a predetermined number of continuous teeth positioned on a side on which the partly untoothed gear starts to mesh which the driven gear when it rotates from a state in which the untoothed portion and the driven gear are opposed to each other, the odd teeth from the untoothed portion side are formed with odd tooth inclined surfaces cut away from the tooth top of the front tooth surface in the direction of rotation of the partly untoothed gear toward the root of the rear tooth surface, and the even teeth are formed with even tooth inclined surfaces cut away from the root of the front tooth surface in the direction of rotation toward the tooth top of the rear tooth surface.