An applied voltage control device includes a potential difference determiner and an applied voltage controller. The potential difference determiner determines a potential difference between a maximum alternating current development voltage and a minimum alternating current development voltage, depending on a developing potential that is an absolute value of a difference between an average electric potential of an alternating current development and an electric potential of a latent image, so as to maintain a constant maximum voltage of a developing bias in the alternating current development. The applied voltage controller controls an alternating current development voltage, applied to move developer from a developer bearer to the latent image, so as to obtain the potential difference determined by the potential difference determiner.